Medical device for cutting substances inside a body lumen

ABSTRACT

A medical device is disclosed for cutting substances inside a body lumen. The medical device includes: a drive shaft that is rotatable; at least one strut that is rotatably connected to a distal side of the drive shaft, the at least one strut extending along a rotation axis, and wherein a central portion of the at least one strut is bent so as to be expandable radially outwardly; and a support portion that is rotatably connected to the distal side of the drive shaft, and wherein the support portion is formed in a mesh shape and a tubular shape while including multiple gaps, at least a portion of which is positioned on a radially inside of the at least one strut, and which is expandable radially outwardly by a central portion in a direction extending along the rotation axis being bent.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Application NumberPCT/JP2015/065888 filed on Jun. 2, 2015, which claims priority toJapanese Application No. 2014-224105 filed on Nov. 4, 2014, and U.S.Provisional Patent Application Ser. No. 62/104,487 filed on Jan. 16,2015, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a medical device for cuttinga substance from an inner wall surface of a body lumen.

BACKGROUND DISCUSSION

Therapy methods for a stenosed site caused by plaque, thrombus or thelike in coronary arteries can include percutaneous transluminal coronaryangioplasty (PTCA) of dilating a blood vessel using a balloon, a methodof causing a mesh-shaped or coil-shaped stent to indwell the bloodvessel as a support for the blood vessel, and the like. However, thesemethods are less likely to be applied, when the plaque of the stenosedsite becomes calcified and hardened or when the stenosed site developsin a bifurcated portion of the coronary arteries. A method, which canenable treatment, can include atherectomy of cutting a stenosissubstance such as the plaque, the thrombus, and the like.

For example, as a device for the atherectomy, JP-T-2003-504090 disclosesa device in which diamond particles (abrasive materials) adhere to anouter surface of a rotating body located in a distal end portion of acatheter and the rotating body is rotated inside the coronary arteriesso as to cut the stenosis substance. The rotating body of this deviceincludes four bars arrayed in the circumferential direction. These barsare expandable so as to fit a diameter of the blood vessel by bendingthe bars to protrude radially outward.

When expandable and contractible bars are used as in the devicedisclosed in JP-T-2003-504090, since an edge of the bars comes intocontact with the blood vessel, a normal blood vessel is at considerablerisk of being damaged. Furthermore, when a hardened stenosis substancesuch as calcified plaque is cut, the hardened stenosis substance iscaught in a gap between the bars, thereby causing an increasingpossibility that the device may be damaged.

SUMMARY

A medical device is disclosed which can be relatively easily deliveredinto a body lumen, which can help ensure a proper cutting range, helpreduce the burden on biological tissues, and help prevent the devicefrom being damaged.

A medical device is disclosed for cutting a substance inside a bodylumen, which can include a drive shaft that is rotatable; at least onestrut that is rotatably connected to a distal side of the drive shaft,that extends along a rotation axis, and whose central portion is bent soas to be expandable radially outward; and a support portion that isrotatably connected to the distal side of the drive shaft that is formedin a mesh shape and a tubular shape while including multiple gaps, atleast a portion of which is positioned on a radially inner side of thestrut, and that is expandable radially outward by a central portion in adirection extending along the rotation axis being bent.

Since the strut is expandable, the medical device having theabove-described configuration can be relatively easily delivered into abody lumen, and can help ensure a proper cutting range by expanding thestrut. Furthermore, since the support portion supports the strut fromthe radially inner side, the medical device can help reduce excessivedamage to biological tissues, which can be caused by an edge of thestrut. The medical device can be prevented from being damaged or brokenby preventing the substances from being caught in the gap of the strut.

If the strut is configured so that a blade for cutting the substances isformed at a position on a further distal side from a portion, whichexpands most radially outward in an expansion state, the blade can beless likely to come into contact with the biological tissues, therebyhelp ensuring safety. The substances can be effectively cut by pressingthe strut into a stenosed site and bringing the blade into contact withthe substances inside the body lumen.

If a maximum expansion portion which expands most radially outward fromthe support portion in an expansion state is caused to protrude radiallyoutward further than the strut from a portion between the struts, themaximum expansion portion of the support portion which has a lowerinfluence on the biological tissues than the strut comes into contactwith the biological tissues. Accordingly, normal biological tissues canbe prevented from being damaged by the edge portion of the strut, andthus can help improve safety.

If the strut in an expansion state is configured so that an outerperipheral surface of the portion having the blade formed therein tiltsradially inward toward the rotating direction side, the strut comes intosmooth contact with a contact target from a side tilting radially inwardin the strut. Accordingly, damage to the biological tissues that iscaused by the strut can be reduced.

If the strut is configured to have a wide portion whose width in therotating direction is relatively wider than that of an adjacent portion,and if the wide portion has the blade formed therein, the wide portioncan help prevent the support portion from protruding radially outward.Accordingly, the blade can be favorably brought into contact with thecontact target without being hindered by the support portion.

If a length in which the maximum expansion portion which expands mostradially outward from the support portion in an expansion stateprotrudes radially outward from the strut is greater than a length inwhich the support portion protrudes radially outward from a portionbetween the struts in the portion having the wide portion arrangedtherein, the maximum expansion portion is brought into contact with thebiological tissues, thereby preventing a normal site from being damagedby the strut. Even so, the blade of the strut can be effectively broughtinto contact with the substances inside the body lumen. Accordingly, thesubstances can be favorably cut.

If the strut is configured to have a tilting portion, which tilts to therotation axis in a contraction state, the outer peripheral surface ofthe strut, can be set to tilt at a desired angle by using an asymmetricshape of the tilting portion in an expansion state, thereby allowing afurther degree of freedom in design. Therefore, the strut can be set tohave an angle by which the biological tissues are less likely to bedamaged and the substances inside the body lumen can be cut relativelyeasily.

If at least any one of the strut and the support portion is covered witha hydrophilic material, at least any one of the cutting unit and thesupport portion is likely to slide on the biological tissues.Accordingly, safety can be improved by preventing the biological tissuesfrom being excessively damaged.

A configuration may be adopted as follows. The drive shaft is a tubularbody. The medical device further has a linear motion shaft, which can bearranged inside the drive shaft, which is movable in the axial directionrelative to the drive shaft, and which is rotatable together with thedrive shaft. The support portion is expandable radially outward byreceiving force acting in the axial direction, which is generated by therelative movement of the drive shaft and the linear motion shaft in theaxial direction. The distal side or the proximal side is not restrictedwhen the strut moves to the drive shaft and the linear motion shaft inthe axial direction. The strut is pressed by the radially outwardexpansion of the support portion so as to expand radially outward.According to this configuration, when the strut expands, a gap is lesslikely to appear between the strut and the support portion, and thus thestenosis substances or substances such as debris or the like are lesslikely to be interposed between the strut and the support portion.Therefore, the medical device can help prevent the strut from beingdamaged, and can help prevent the normal biological tissues from beingdamaged by the edge portion of the strut.

A configuration may be adopted as follows. The drive shaft is a tubularbody. The medical device further has a linear motion shaft which can bearranged inside the drive shaft, which is movable in the axial directionrelative to the drive shaft, and which is rotatable together with thedrive shaft, and an inner tube which is a tubular body arranged insidethe drive shaft, and whose rotation is not restricted with respect tothe drive shaft and the linear motion shaft. According to thisconfiguration, in the medical device, even when the drive shaft and thelinear motion shaft are rotated, the inner tube is not rotated, and arotating force is not applied to a wire or the like inserted into theinner tube. Therefore, the medical device can help prevent the wire orthe like inserted into the inner tube from being worn, and can helpprevent the rotated wire or the like from becoming less likely to beremoved from the inner tube. In addition, since the inner tube is notrotated, poor operability can be prevented by preventing the blood fromcoagulating inside the lumen. In addition, since the inner tube intowhich the wire or the like is inserted is not rotated, the medicaldevice can help prevent the blood vessel from being damaged bypreventing the wire or the like from being moved in the axial directionby receiving a frictional force from the inner tube.

The medical device may be configured to have a contrast portion havingan X-ray contrast material disposed in a portion of the strut or thesupport portion. According to this configuration, a position or anexpansion diameter of the strut and the support portion can beaccurately recognized by using X-ray fluoroscopy, thereby furtherimproving manual skills.

The medical device may be configured to further have a distal tube whichis disposed on the further distal side from the strut, which has atubular shape, whose outer peripheral surface has multiple convexportions formed thereon, and which is rotatable together with the driveshaft. According to this configuration, a stenosed site can also be cutby the distal tube, thereby helping enable the stenosed site to bequickly cut.

A treatment method is disclosed for cutting substances inside a bodylumen by using a medical device including a drive shaft that isrotatable, at least one strut that is rotatably connected to a distalside of the drive shaft, that extends along a rotation axis, and whosecentral portion is bent so as to be expandable radially outward, asupport portion that is rotatably driven by the drive shaft, that isformed in a mesh shape and a tubular shape while including multiplegaps, a portion of which is positioned on a radially inner side of theat least one strut, and that is expandable radially outward by a centralportion in a direction extending along the rotation axis being bent, adetection unit that detects resistance including at least one ofrotating direction resistance and axial direction resistance which acton the at least one strut, the treatment method comprising: insertingthe at least one strut and the support portion which are in a contractedstate into the body lumen; expanding the at least one strut and thesupport portion; cutting the substances while repeatedly pushing andpulling the substances inside the body lumen by causing the drive shaftto rotate the at least one strut and the support portion; causing thedetection unit to detect the resistance; stopping the rotation of the atleast one strut and the support portion when the resistance exceeds apreset threshold value or giving a notification that the resistanceexceeds the threshold value; and contracting the at least one strut andthe support portion and removing the at least one strut and the supportportion from the inside of the body lumen.

A treatment method is disclosed for cutting substances inside a bodylumen, the method comprising: inserting at least one strut of a medicaldevice into the body lumen in a contracted state, the medical deviceincluding a drive shaft that is rotatable, the at least one strut thatis rotatably connected to a distal side of the drive shaft, that extendsalong a rotation axis, and whose central portion is bent so as to beexpandable radially outward, a support portion that is rotatably drivenby the drive shaft, that is formed in a mesh shape and a tubular shapewhile including multiple gaps, a portion of which is positioned on aradially inner side of the at least one strut, and that is expandableradially outward by a central portion in a direction extending along therotation axis being bent, a detection unit that detects resistanceincluding at least one of rotating direction resistance and axialdirection resistance which act on the at least one strut; expanding theat least one strut and the support portion; cutting the substances whilerepeatedly pushing and pulling the substances inside the body lumen bycausing the drive shaft to rotate the at least one strut and the supportportion; detecting the resistance of at least one of the rotatingdirection resistance and the axial direction resistance which act on theat least one strut with the detection unit; and stopping the rotation ofthe at least one strut and the support portion when the resistanceexceeds a preset threshold value or giving a notification that theresistance exceeds the threshold value.

A medical device is disclosed for cutting substances inside a bodylumen, the medical device comprising: a drive shaft that is rotatable;at least one strut that is rotatably connected to a distal side of thedrive shaft, that extends along a rotation axis, and whose centralportion is bent so as to be expandable radially outward; a supportportion that is rotatably driven by the drive shaft, that is formed in amesh shape and a tubular shape while including multiple gaps, a portionof which is positioned on a radially inner side of the at least onestrut, and that is expandable radially outward by a central portion in adirection extending along the rotation axis being bent; and a detectionunit that detects resistance including at least one of rotatingdirection resistance and axial direction resistance which act on the atleast one strut.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a state where a cutting unit of amedical device according to a first embodiment contracts.

FIG. 2 is a plan view illustrating a state where a cutting unit of atreatment device expands.

FIG. 3A is a plan view illustrating a distal end portion of thetreatment device in a state where the cutting unit is accommodated in anouter sheath.

FIG. 3B is a plan view illustrating a distal end portion of thetreatment device in a state where the contracting cutting unit protrudesfrom the outer sheath.

FIG. 3C is a plan view illustrating a distal end portion of thetreatment device in a state where the cutting unit protruding from theouter sheath expands.

FIG. 4 is a longitudinal sectional view illustrating the distal endportion of the treatment device.

FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 3B.

FIG. 6A is a cross-sectional view of the treatment device in anexpansion state taken along line 6A-6A in FIG. 3C.

FIG. 6B is a cross-sectional view of the treatment device in anexpansion state taken along line 6B-6B in FIG. 3C.

FIG. 7 is a plan view illustrating a filter device.

FIG. 8A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where a guidewire isinserted into the blood vessel.

FIG. 8B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where a guiding catheter isinserted into the blood vessel.

FIG. 9A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where a support catheter isinserted into a stenosed site.

FIG. 9B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where the filter device isinserted into the blood vessel.

FIG. 10A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where a filter portionexpands.

FIG. 10B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where the treatment deviceis inserted into the blood vessel.

FIG. 11A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where the cutting unit ofthe treatment device and a support portion are exposed.

FIG. 11B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where the cutting unit andthe support portion expand.

FIG. 12A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where stenosis substancesare cut by the treatment device.

FIG. 12B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state where the cutting unit isaccommodated by the outer sheath.

FIG. 13A is schematic sectional view illustrating an intravascular statewhen manual skills are used in a state when debris collected in thefilter portion is aspirated by a catheter.

FIG. 13B is schematic sectional view illustrating an intravascular statewhen manual skills are used in a state where the filter portion isaccommodated inside a tubular body.

FIG. 14 is a plan view illustrating a state where a cutting unit of amedical device according to a second embodiment contracts.

FIG. 15 is a longitudinal sectional view illustrating a distal endportion of the medical device according to the second embodiment.

FIG. 16 is a longitudinal sectional view illustrating a proximal portionof a treatment device according to the second embodiment.

FIG. 17 is a plan view illustrating a drive shaft according to thesecond embodiment.

FIG. 18 is a plan view illustrating another example of the drive shaftaccording to the second embodiment.

FIG. 19 is a cross-sectional view of the treatment device along line19-19 in FIG. 16.

FIG. 20A is a longitudinal sectional view illustrating the treatmentdevice in a state before a distal tube comes into contact with a cuttingunit.

FIG. 20B is a longitudinal sectional view illustrating the treatmentdevice in a state after the distal tube comes into contact with thecutting unit.

FIG. 21 is a longitudinal sectional view illustrating a liquid supplyunit according to the second embodiment.

FIG. 22 is a longitudinal sectional view illustrating the distal endportion of the treatment device according to the second embodiment whenpriming is performed.

FIG. 23 is a longitudinal sectional view illustrating the proximalportion of the treatment device according to the second embodiment whenthe priming is performed.

FIG. 24A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the treatment deviceis inserted into the blood vessel.

FIG. 24B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit andthe support portion of the treatment device are exposed.

FIG. 25 is a longitudinal sectional view illustrating the proximalportion when a dial of the treatment device according to the secondembodiment is rotated.

FIG. 26A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit andthe support portion expand.

FIG. 26B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when stenosis substancesare cut by the treatment device.

FIG. 27A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit andthe support portion are pulled out from a stenosed site, and

FIG. 27B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when stenosis substancesare cut by the treatment device.

FIG. 28A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit andthe support portion are pulled out from a stenosed site.

FIG. 28B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit andthe support portion expand further.

FIG. 29A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when stenosis substancesare cut by the treatment device.

FIG. 29B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when stenosis substanceshave been cut by the treatment device.

FIG. 30A is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the cutting unit isaccommodated by the outer sheath.

FIG. 30B is a schematic sectional view illustrating an intravascularstate when manual skills are used in a state when the filter portion isaccommodated inside a tubular body.

FIG. 31 is a plan view illustrating a modification example of themedical device according to the first embodiment.

FIG. 32 is a cross-sectional view illustrating another modificationexample of the medical device according to the first embodiment.

FIG. 33 is a longitudinal sectional view illustrating a modificationexample of the medical device according to the second embodiment.

FIG. 34 is a plan view illustrating another modification example of themedical device according to the second embodiment.

FIG. 35 is a cross-sectional view illustrating further anothermodification example of the medical device according to the secondembodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings. In order to facilitate description,dimensional ratios in the drawings are exaggerated, and thus aredifferent from actual ratios in some cases.

First Embodiment

A medical device 10 according to a first embodiment of the presentdisclosure can be used for therapy (treatment) to cut a stenosed site oran occluded site which is caused by plaque, thrombus or the like insidethe blood vessel. In this description, a side of the device which isinserted into the blood vessel is referred to as a “distal side”, and anoperating hand side is referred to as a “proximal side”.

As illustrated in FIG. 1, the medical device 10 according to the firstembodiment of the present disclosure can include a treatment device 20which cuts a stenosed site or an occluded site, and a filter device 30which collects debris (substance) which is cut and dropped off from thestenosed site or the occluded site.

As illustrated in FIGS. 1 and 2, the treatment device 20 can include acutting unit 40 which is expandable and contractible radially outward, asupport portion 50 which supports the cutting unit 40, a drive shaft 60which rotates the cutting unit 40, a linear motion shaft 70 whichadjusts a deformation amount of the cutting unit 40, a distal tube 75which interlocks with a distal side of the linear shaft 70, an outersheath 80 which can accommodate the cutting unit 40, and an operationunit 90 which is disposed on an operating hand side for operation.

As illustrated in FIGS. 3A to 6B, the cutting unit 40 can include atleast one (four in the present embodiment) strut 41 which extends alonga rotation axis X of the drive shaft 60, a tubular distal fixed end 42which is formed integrally with the strut 41 on a distal side of each ofthe plurality of struts 41, and a tubular proximal fixed end 43 which isformed integrally with the strut 41 on a proximal side of each of theplurality of struts 41. If the distal fixed end 42 and the proximalfixed end 43 are moved closer to each other, the strut 41 can shift froma contraction state (refer to FIGS. 3B and 5) of having a substantiallylinear shape to an expansion state (refer to FIGS. 3C, 6A, and 6B) ofbeing deformed so as to be bent radially outward.

In the strut 41, a tilting portion 44 which is curved so as to tilt tothe rotation axis X in a contraction state is formed on the proximalside, and multiple opening portions 45 which penetrate an innerperipheral surface from an outer peripheral surface are formed on thedistal side. The strut 41 has wide portions 46 whose width in thecircumferential direction (rotating direction Y) is relatively widerthan that of the adjacent portion. The opening portions 45 arerespectively formed in the wide portions 46. The opening portion 45 isformed at multiple locations (four or five locations in the presentembodiment) along the extending direction of the strut 41. An inner edgeportion of the opening portion 45 functions as a blade 47 for cutting astenosed site or an occluded site. A position where the blade 47 of thestrut 41 is formed is located on the further distal side from a portionwhere an outer diameter of the strut 41 is maximized in an expansionstate (substantially central portion in a direction extending along therotation axis X). In accordance with an exemplary embodiment, it can bepreferable to chamfer an edge portion other than the inner edge portionconfiguring the blade 47 of the opening portion 45 in the strut 41.

The strut 41 having four opening portions 45 formed therein and thestrut 41 having five opening portions 45 formed therein are alternatelyarranged in the circumferential direction. Therefore, when the cuttingunit 40 is cut out from one tubular body by means of laser processing,machining or the like, the four opening portions 45 and the five openingportions 45 can be alternately arranged so as to be shifted from eachother, thereby enabling the opening portion 45 to secure a suitablewidth. In addition, since the blade 47 of the strut 41 adjacent in thecircumferential direction is arranged so as to be shifted, apredetermined portion can be prevented from being unevenly cut off.Accordingly, a stenosed site or an occluded site can be effectively cut.

If the strut 41 is brought into an expansion state, an outer peripheralsurface of a portion having the blade 47 formed therein is deformed soas to tilt radially inward as it goes toward a side in the rotatingdirection Y (refer to FIG. 6B). Therefore, when the strut 41 is rotatedin the expansion state, the strut 41 can come into smooth contact with acontact target from a side tilting radially inward in the strut 41.Accordingly, excessive damage to biological tissues can be reduced. Inaddition, since the strut 41 is formed by being cut out from a tubularbody having a diameter which is smaller than a diameter in the expansionstate, the radius of curvature of the outer peripheral surface of thestrut 41 is smaller than a distance from the rotation axis X to theouter peripheral surface of the strut 41 in the expansion state.Therefore, an edge portion of the strut 41 becomes further less likelyto come into contact with the contact target. Accordingly, excessivedamage to biological tissues can be further reduced.

For example, as a configuration material of the cutting unit 40, a shapememory alloy which is provided with a shape memory effect orsuper-elasticity by means of heat treatment, stainless steel, or thelike can be preferably used. As the shape memory alloy, Ni—Ti-basedalloys, Cu—Al—Ni-based alloys, Cu—Zn—Al-based alloys, combinationsthereof, or the like are preferably used.

The support portion 50 is arranged so as to support the cutting unit 40radially inward from the cutting unit 40, is formed by braiding multiplewires 51, and is formed in a tubular shape so as to have a gap 52between the wires 51. A distal end portion 54 of the support portion 50is configured so that the multiple wires 51 gather into a tubular shape,and is fixed to an inner side surface of the distal fixed end 42 of thestrut 41 and the outer peripheral surface of the linear motion shaft 70(refer to FIG. 4). A proximal end portion 55 of the support portion 50is configured so that the multiple wires 51 gather into a tubular shape,and is fixed to an inner peripheral surface of the proximal fixed end 43of the strut 41.

If the distal fixed end 42 and the proximal fixed end 43 are moved closeto each other, the support portion 50 can shift from a contraction state(refer to FIG. 3B) where the support portion has a tubular shape havinga substantially uniform outer diameter to an expansion state (refer toFIGS. 3C and 4) where the support portion 50 is deformed so that acentral portion of the support portion 50 is bent radially outward.

A maximum expansion portion 53 whose outer diameter is largest in thesupport portion 50 in the expansion state protrudes radially outwardbetween the struts 41 since a gap between the struts 41 in the expansionstate increases (refer to FIG. 6A). Therefore, a portion which expandsoutward most in the strut 41 in the expansion state and is likely tocome into contact with biological tissues is located further radiallyinward from the maximum expansion portion 53 of the support portion 50.Accordingly, normal biological tissues can be prevented from beingdamaged by the edge portion of the strut 41.

Then, in a portion in the vicinity of the blade 47 of the strut 41, adistance from the rotation axis X is short (diameter is small), and thewide portion 46 is formed. Accordingly, a gap between the struts 41 isnarrow. Thus, the support portion 50 located in the vicinity of theblade 47 is prevented from protruding radially outward from the portionbetween the struts 41. Therefore, the blade 47 can be brought intocontact with a contact target without being hindered by the supportportion 50 (refer to FIG. 6B).

In order not to cause damage to the biological tissues in contact, it ispreferable to form the wire 51 so that rigidity of the wire 51 is lowerthan that of the strut 41 and a corner portion in a cross section hasthe curvature, and is more preferable to form the wire 51 so that thecross section has a circular shape.

For example, an outer diameter of the wire 51 is 0.05 mm to 0.15 mm,although the outer diameter can be optionally selected depending onmaterials, application conditions or the like of the wire 51.

A configuration material of the wire 51 is preferably a flexiblematerial. For example, a shape memory alloy which is provided with ashape memory effect or super-elasticity by means of heat treatment,stainless steel, Ta, Ti, Pt, Au, W, polyolefin such as polyethylene,polypropylene and the like, polyamide, polyester such as polyethyleneterephthalate or the like, fluorine-based polymer such as ETFE and thelike, polyether ether ketone (PEEK), polyimide, or the like can bepreferably used. As the shape memory alloy, Ni—Ti-based alloys,Cu—Al—Ni-based alloys, Cu—Zn—Al-based alloys, combinations thereof, orthe like are preferably used. For example, structures having multiplematerials combined therewith include a structure in which a core wiremade of Pt is covered with Ni—Ti alloy in order to provide contrast, anda structure a core wire made of Ni—Ti alloy is subjected to goldplating.

For example, an inner diameter of the cutting unit 40 in a contractionstate is 0.9 mm to 1.6 mm, although the inner diameter can be optionallyselected depending on each inner diameter of applied body lumens or thelike. As an example, the inner diameter can be set to 1.4 mm. Forexample, an outer diameter of the cutting unit 40 in the contractionstate is 1.1 mm to 1.8 mm, although the outer diameter can be optionallyselected depending on each inner diameter of applied body lumens or thelike. As an example, the inner diameter can be set to 1.7 mm. Forexample, a length of the cutting unit 40 in a direction extending alongthe rotation axis X is 10 mm to 30 mm, although the length can beoptionally selected depending on applications. As an example, the lengthcan be set to 20 mm.

For example, the maximum outer diameter of the cutting unit 40 in anexpansion state is 3.0 mm to 8.0 mm, although the maximum outer diametercan be optionally selected depending on each inner diameter of appliedbody lumens or the like. As an example, the maximum outer diameter canbe set to 7.0 mm.

For example, a length in which the maximum expansion portion 53 of thesupport portion 50 in the expansion state protrudes radially outwardfrom the strut 41 is 0.05 mm to 0.5 mm, although the length can beoptionally selected. As an example, the length can be set to 0.2 mm.

As illustrated in FIGS. 1 to 4, the drive shaft 60 is formed in atubular shape, a distal side of the drive shaft 60 is fixed to theproximal fixed end 43 of the cutting unit 40, and a driven gear 61 isfixed to a proximal side of the drive shaft 60. A proximal portion ofthe drive shaft 60 rotatably interlocks with a casing 91 of theoperation unit 90.

The drive shaft 60 is flexible. Moreover, the drive shaft 60 hasproperties in which rotational power acting from the proximal side canbe transmitted to the distal side. For example, the drive shaft 60 isconfigured to include a tubular body having a shape of a multi-layercoil such as a three-layer coil or the like whose winding directions arealternately rightward, leftward, and rightward, and a reinforcing memberincorporated in the drive shaft 60 such as wires or the like made ofpolyolefin such as polyethylene, polypropylene and the like, polyamide,polyester such as polyethylene terephthalate or the like, fluorine-basedpolymer such as ETFE and the like, polyether ether ketone (PEEK),polyimide, or combinations thereof.

For example, an inner diameter of the drive shaft 60 is 0.7 mm to 1.4mm, although the inner diameter can be optionally selected. As anexample, the inner diameter can be set to 1.2 mm. For example, an outerdiameter of the drive shaft 60 is 0.8 mm to 1.5 mm, although the outerdiameter can be optionally selected. As an example, the outer diametercan be set to 1.35 mm.

The linear motion shaft 70 is a tubular body which can move in thedirection of the rotation axis X relative to the drive shaft 60 in orderto expand and contract the cutting unit 40 and the support portion 50.The linear motion shaft 70 penetrates the drive shaft 60, the cuttingunit 40, and the support portion 50. In the linear motion shaft 70, adistal side of the linear motion shaft 70 is fixed to the distal endportion 54 of the wire 51, and a proximal side of the linear motionshaft 70 is connected to a moving mechanism 92 which linearly moves thelinear motion shaft 70 along the rotation axis X. The linear shaft 70internally has a lumen 72 into which a guidewire can be inserted.

A configuration material of the linear motion shaft 70 is preferably aflexible material. For example, a shape memory alloy which is providedwith a shape memory effect or super-elasticity by means of heattreatment, stainless steel, Ta, Ti, Pt, Au, W, polyolefin such aspolyethylene, polypropylene and the like, polyamide, polyester such aspolyethylene terephthalate or the like, fluorine-based polymer such asETFE and the like, polyether ether ketone (PEEK), polyimide, or the likecan be preferably used. As the shape memory alloy, Ni—Ti-based alloys,Cu—Al—Ni-based alloys, Cu—Zn—Al-based alloys, combinations thereof, orthe like are preferably used. In addition, the linear motion shaft 70may be configured to include multiple materials, or a reinforcingmaterial such as a wire or the like may be incorporated therein.

For example, an inner diameter of the linear motion shaft 70 is 0.5 mmto 1.2 mm, although the inner diameter can be optionally selected. As anexample, the inner diameter can be set to 0.95 mm. For example, an outerdiameter of the linear motion shaft 70 is 0.6 mm to 1.3 mm, although theouter diameter can be optionally selected. As an example, the outerdiameter can be set to 1.05 mm.

The outer sheath 80 is a tubular body for covering the outer side of thedrive shaft 60, and is movable and rotatable with respect to the driveshaft 60 in a direction extending along the rotation axis X. The outersheath 80 is operable by gripping the proximal portion. The outer sheath80 can internally accommodate the cutting unit 40 and the supportportion 50 in a contraction state by being moved to the distal side. Thecutting unit 40 and the support portion 50 can be exposed outward bymoving the outer sheath 80 to the proximal side.

A configuration material of the outer sheath 80 is not particularlylimited. However, for example, polyolefin such as polyethylene,polypropylene and the like, polyamide, polyester such as polyethyleneterephthalate or the like, fluorine-based polymer such as ETFE and thelike, polyether ether ketone (PEEK), polyimide, or the like can bepreferably used. In addition, the outer sheath 80 may be configured toinclude multiple materials, or a reinforcing material such as a wire orthe like may be incorporated therein.

For example, an inner diameter of the outer sheath 80 can be 1.2 mm to1.9 mm, although the inner diameter can be optionally selected. As anexample, the inner diameter can be set to 1.8 mm. For example, an outerdiameter of the outer sheath 80 can be 1.3 mm to 2.0 mm, although theouter diameter can be optionally selected. As an example, the outerdiameter can be set to 2.0 mm.

The distal tube 75 is fixed to the distal side of the linear motionshaft 70. A lumen 76 is formed inside the distal tube 75. The lumen 76communicates with the lumen 72 of the linear motion shaft 70.

A configuration material of the distal tube 75 is not particularlylimited. However, for example, polyolefin such as polyethylene,polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetatecopolymer, or the like polyvinyl chloride, polystyrene, polyamide,polyimide, combinations thereof, or the like can be preferably used.

As illustrated in FIGS. 1 and 2, the operation unit 90 can include thecasing 91, a drive mechanism 93 which provides the drive shaft 60 with arotating force, and the moving mechanism 92 which moves the linearmotion shaft 70 along the rotation axis X.

The drive mechanism 93 can include a drive gear 94 which meshes with thedriven gear 61, a motor 96 which serves as a drive source including arotary shaft 95 to which the drive gear 94 is fixed, a battery 97 suchas an electric cell or the like which supplies power to the motor 96,and a switch 98 which controls driving of the motor 96. The switch 98 isturned on and the rotary shaft 95 of the motor 96 is rotated, therebyrotating the driven gear 61 meshing with the drive gear 94 and rotatingthe drive shaft 60. If the drive shaft 60 is rotated, the cutting unit40, the support portion 50, and the distal tube 75, which are fixed tothe distal side of the drive shaft 60.

The moving mechanism 92 can include a dial 100 which can be rotated byan operator's finger, a rotatable feed screw 101, which coaxiallyinterlocks with the dial 100, a moving base 102 which is linearlymovable by the feed screw 101, and a bearing portion 103 which is fixedto the moving base 102 and which rotatably supports the linear motionshaft 70.

The dial 100 is rotatably held inside the casing 91, and an outerperipheral surface of the dial 100 is exposed from an opening portion104 formed in the casing 91. The dial 100 is rotatable by the fingeroperating the outer peripheral surface. The feed screw 101 is rotatablyheld inside the casing 91. The moving base 102 has a female screw towhich the feed screw 101 is screwed, is not rotatable with respect tothe casing 91, and is linearly movable along the rotation axis X. Thebearing portion 103, which is fixed to the moving base 102 applies amoving force to the linear motion shaft 70 in response to the movementof the moving base 102. Accordingly, it is preferable to use a thrustbearing which can receive a thrust force.

As illustrated in FIGS. 1 and 7, the filter device 30 can include afilter instrument 110 which has a function as a filter, and a sheath 120which can accommodate the filter instrument 110.

The filter instrument 110 can include a filter portion 111 which isobtained by braiding multiple element wires 112, and an elongated shaft113 which interlocks with the filter portion 111 by penetrating thefilter portion 111.

The filter portion 111 can contract when being accommodated inside thesheath 120, and can expand by using a self-expansion force when beingreleased from the sheath 120. In the filter portion 111, a distal sideis shaped into a closed cage and interlocks with the shaft portion 113,and a proximal side interlocks with the shaft portion 113 by themultiple element wires 112 being collectively twisted.

An outer diameter of the element wire 112 can be optionally selecteddepending on materials, usage, or the like of the element wire 112.However, for example, the outer diameter is 20 μm to 100 μm. As anexample, the outer diameter can be set to 40 μm.

A configuration material of the element wire 112 is preferably aflexible material. For example, a shape memory alloy which is providedwith a shape memory effect or super-elasticity by means of heattreatment, stainless steel, Ta, Ti, Pt, Au, W, polyolefin such aspolyethylene, polypropylene and the like, polyamide, polyester such aspolyethylene terephthalate or the like, fluorine-based polymer such asETFE and the like, polyether ether ketone (PEEK), polyimide, or the likecan be preferably used. As the shape memory alloy, Ni—Ti-based alloys,Cu—Al—Ni-based alloys, Cu—Zn—Al-based alloys, combinations thereof, orthe like are preferably used. For example, structures having multiplematerials combined therewith include a structure in which a core wiremade of Pt is covered with Ni—Ti alloy in order to provide contrast, anda structure a core wire made of Ni—Ti alloy is subjected to goldplating.

A configuration material of the shaft portion 113 is not particularlylimited. However, for example, stainless steel, a shape memory alloy, orthe like can be preferably used.

The sheath 120 can include a tubular body 121, a hub 122, and a kinkresistant protector 123. The tubular body 121 can include a lumen 124which can accommodate the filter instrument 110, and is open in atubular body opening portion 126 formed in the distal end portion. Thehub 122 is fixed to the proximal end portion of the tubular body 121,and can include a hub opening portion 125, which communicates with thelumen 124. The kink resistant protector 123 can be a flexible member forcovering an interlock portion between the tubular body 121 and the hub122, and can help prevent kinking of the tubular body 121.

A configuration material of the tubular body 121 is not particularlylimited. However, for example, polyolefin such as polyethylene,polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetatecopolymer, or the like, polyvinyl chloride, polystyrene, polyamide,polyimide, combinations thereof, or the like can be preferably used.

Next, a method of using the medical device 10 according to the presentembodiment will be described by exemplifying a case where stenosissubstances inside the blood vessel are cut.

First, an introducer sheath (not illustrated) is percutaneously insertedinto the blood vessel on a further upstream side (proximal side) from astenosed site S in the blood vessel. A guidewire 130 is inserted intothe blood vessel via the introducer sheath. Then, the guidewire 130 ispushed so as to move forward and reach a proximal side of the stenosedsite S, as illustrated in FIG. 8A. Thereafter, a proximal end portion ofthe guidewire 130, which is located outside the body is inserted into acatheter opening portion 141 on a distal side of a guiding catheter 140.As illustrated in FIG. 8B, the guiding catheter 140 is inserted into theblood vessel along the guidewire 130 so as to reach the proximal side ofthe stenosed site S.

Next, the proximal end portion of the guidewire 130, which is locatedoutside the body is inserted into a catheter opening portion 151 on adistal side of a support catheter 150, and the support catheter 150 ispushed to move forward to the proximal side of the stenosed site S.Thereafter, as illustrated in FIG. 9A, the support catheter 150 and theguidewire 130 are caused to reach a further distal side from thestenosed site S. Thereafter, the guidewire 130 is removed therefrom in astate where the support catheter 150 remains inside the blood vessel.

Then, the filter device 30 in which the filter instrument 110 isaccommodated inside the sheath 120 is prepared. The filter portion 111is arranged at a position close to the distal end portion of the tubularbody 121 of the sheath 120, and a shape of the filter portion 111 isrestricted to a contraction state. Then, as illustrated in FIG. 9B, thefilter device 30 is inserted into the blood vessel via the supportcatheter 150 so as to reach the further distal side from the stenosedsite S. Thereafter, the support catheter 150 is removed therefrom.

Next, the sheath 120 is moved to the proximal side relative to thefilter instrument 110 so that the filter portion 111 protrudes to thedistal side from the tubular body 121. In this manner, as illustrated inFIG. 10A, the filter portion 111 is brought into an expansion state byusing its own restoring force. An outer peripheral portion of the filterportion 111 which is shaped into a cage comes into contact with an innerwall surface of the blood vessel. At this time, the filter portion 111is open toward the stenosed site S on the upstream side (proximal side).Thereafter, the sheath 120 is removed therefrom by leaving the filterinstrument 110 behind.

Next, the treatment device 20 in a state where the cutting unit 40 andthe support portion 50 contracts and are accommodated inside the outersheath 80 is prepared. The proximal end portion of the shaft portion 113is inserted into the distal side opening portion of the distal tube 75.As illustrated in FIG. 10B, the proximal end portion of the shaftportion 113 is caused to reach the inside of the blood vessel via theguiding catheter 140. Then, as illustrated in FIG. 11A, the outer sheath80 is moved to the proximal side, and the cutting unit 40 and thesupport portion 50 are exposed inside the blood vessel. In this state,the cutting unit 40 and the support portion 50 are in a contractionstate. Thereafter, if the dial 100 is rotated as illustrated in FIG. 2,the feed screw 101 is rotated, the moving base 102 is moved to theproximal side, and the linear motion shaft 70 interlocking with themoving base 102 is moved to the proximal side. If the linear motionshaft 70 is moved to the proximal side, the distal fixed end 42 of thecutting unit 40 moves so as to be closer to the proximal fixed end 43.As illustrated in FIG. 11B, the cutting unit 40 and the support portion50 are brought into a state of expanding radially outward. A size of thecutting unit 40 and the support portion 50 can be optionally adjusteddepending on a rotation amount of the dial 100. In this way, as comparedto a case of cutting by using a rotating body in which an abrasivematerial or the like adheres to an outer surface of a balloon whosediameter is regulated during expansion, the cutting unit 40 caneffectively perform cutting, since a size during the expansion can beoptionally adjusted to a desirable size.

Next, if the switch 98 of the operation unit 90 is turned on, a drivingforce of the motor 96 is transmitted from the drive gear 94 to thedriven gear 61, the drive shaft 60 interlocking with the driven gear 61is rotated, and the cutting unit 40 and the support portion 50 whichinterlock with the drive shaft 60 are rotated. If the cutting unit 40and the support portion 50 are rotated, the linear motion shaft 70interlocking with both of these on the distal side is also rotated. Theproximal portion of the linear motion shaft 70 is supported by thebearing portion 103. Accordingly, even when being rotated, the cuttingunit 40 and the support portion 50 can maintain an expansion state.

Next, in a state where the cutting unit 40 and the support portion 50are rotated, the treatment device 20 is pushed so as to move forward asillustrated in FIG. 12A. In this manner, the blade 47 formed in thecutting unit 40 comes into contact with the stenosed site S and cutstenosis substances. The stenosis substances are changed to debris D soas to flow to the distal side (downstream side). The debris D flowing tothe distal side enters the inside of the filter portion 111 located onthe distal side, and is filtered and collected by the filter portion111. In this manner, the debris D can be prevented from flowing to theperipheral blood vessel. Accordingly, a new stenosed site can beprevented from developing in the peripheral blood vessel.

Then, when the stenosed site S is cut, the maximum expansion portion 53whose outer diameter is largest in the support portion 50 protrudesradially outward between the struts 41. A portion which expands outwardmost in the strut 41 and is likely to come into contact with biologicaltissues is located further radially inward from the maximum expansionportion 53 (refer to FIG. 6A). In this manner, the maximum expansionportion 53 of the support portion 50, which has a lower influence on thebiological tissues than the strut 41 comes into contact with thebiological tissues. Accordingly, normal biological tissues can beprevented from being damaged by the edge portion of the strut 41, andthus, safety can be improved. In addition, since the blade 47 is notformed in a portion which expands outward most in the strut 41 and whichis likely to come into contact with biological tissues, normalbiological tissues can be prevented from being damaged, and thus safetycan be improved. Furthermore, a portion in the vicinity of the blade 47of the strut 41 has a short distance from the rotation axis X (diameteris small), and has the wide portion 46 formed therein. Accordingly, thesupport portion 50 is less likely to protrude radially outward betweenthe struts 41. Therefore, the blade 47 can be brought into contact withthe stenosed site S without hindering the support portion 50.

In addition, in the strut 41, the outer peripheral surface having theblade 47 formed therein is deformed so as to tilt radially inward as itgoes toward a side in the rotating direction Y (refer to FIG. 6B).Therefore, the strut 41 comes into smooth contact with a contact targetsuch as the stenosed site S, the biological tissues, or the like from aside tilting radially inward in the strut 41. Accordingly, excessivedamage to the biological tissues can be reduced. In addition, since thestrut 41 is formed by being cut out from a tubular body having adiameter which is smaller than a diameter in the expansion state, theradius of curvature of the outer peripheral surface of the strut 41 issmaller than a distance from the rotation axis X to the outer peripheralsurface of the strut 41 in the expansion state. Therefore, the edgeportion of the strut 41 becomes further less likely to come into contactwith the contact target. Accordingly, excessive damage to the biologicaltissues can be further reduced.

In addition, the support portion 50 is disposed on the inner side of thestrut 41. Accordingly, the dropped hard debris D is less likely to beinterposed between the struts 41, and the strut 41 is not rolled upoutward. Therefore, the strut 41 can be prevented from being damaged orbroken.

In addition, since the strut 41 having the blade 47 formed therein issupported by the support portion 50, a radial force (force acting in theradial direction) increases. Accordingly, regardless of the expandableand contractible structure, improved cutting capability can bedemonstrated. In addition, a gap between the struts 41 is complementedby the support portion 50. Accordingly, as a whole, the cross sectionformed by the strut 41 and the support portion 50 becomes substantiallycircular, thereby enabling the cutting unit 40 to be centered at asuitable position. In addition, a portion of the debris D cut off andgenerated by the blade 47 of the strut 41 can be collected into thesupport portion 50.

After the stenosis substances are completely cut, the switch 98 isturned off, and the rotation of the drive shaft 60 is stopped. Then, ifthe dial 100 is rotated in reverse as compared to when the cutting unit40 and the support portion 50 expand, as illustrated in FIG. 1, the feedscrew 101 is rotated, the moving base 102 is moved to the distal side,and the linear motion shaft 70 interlocking with the moving base 102 ismoved to the distal side. If the linear motion shaft 70 is moved to thedistal side, the distal fixed end 42 of the cutting unit 40 moves so asto be separated from the proximal fixed end 43, and the cutting unit 40and the support portion 50 are brought into a state of contractingradially inward. Thereafter, the outer sheath 80 is moved to the distalside. As illustrated in FIG. 12B, the cutting unit 40 and the supportportion 50 are accommodated inside the outer sheath 80, and thetreatment device 20 is removed therefrom via the guiding catheter 140.

Next, the proximal end portion of the shaft portion 113 is inserted intothe tubular body opening portion 126 of the sheath 120 (suctioncatheter). As illustrated in FIG. 13A, the sheath 120 is inserted intothe blood vessel via the guiding catheter 140. In this state, aY-connector (not illustrated) is connected to the sheath 120 so as tocommunicate with the hub opening portion 125 of the sheath 120, and asyringe is connected to an opening portion into which the shaft portion113 of the Y-connector is not inserted. Thereafter, if a suction forceis applied by pulling out a pusher of the syringe, negative pressure isgenerated inside the lumen 124 extending from the distal side to theproximal side. Accordingly, the debris D inside the filter portion 111can be pulled into the lumen 124 through the tubular body openingportion 126. When the debris D is aspirated by using the syringe, thetubular body 121 is moved forward and rearward, if necessary. In thismanner, the debris D can be aspirated effectively. As described above,the debris D inside the filter portion 111 is partially or completelyaspirated, and is pulled into the lumen 124, thereby bringing the filterportion 111 into a state where the filter portion 111 is likely tocontract. An instrument (suction catheter) for aspirating the debris Dmay be a catheter which is different from the sheath 120. In addition,without being limited to the syringe, an instrument for applying asuction force may be a pump, for example.

Next, if the shaft portion 113 is moved to the distal side relative tothe sheath 120, as illustrated in FIG. 13B, the filter portion 111 ispulled out by the shaft portion 113, and is moved into the lumen 124 ofthe tubular body 121.

Thereafter, the filter instrument 110 is removed therefrom together withthe sheath 120. The guiding catheter 140 and the introducer sheath areremoved therefrom, thereby causing a user to finish manual skills. Thefilter instrument 110 may not be accommodated in the sheath 120. Insteadof using the sheath 120, the filter instrument 110 may be directlyaccommodated inside the guiding catheter 140. In this case, the debris Dmay not be aspirated and removed therefrom.

As described above, the medical device 10 according to the firstembodiment is a device for cutting substances inside a body lumen. Themedical device 10 can include the drive shaft 60 that is rotatable, atleast one strut 41 that rotatably interlocks with the distal side of thedrive shaft 60, that extends along a rotation axis X, and whose centralportion is bent so as to be expandable radially outward, and the supportportion 50 that rotatably interlocks with the distal side of the driveshaft 60, that is formed in a mesh shape and a tubular shape whileincluding multiple gaps, at least a portion of which is positioned on aradially inner side of the strut 41, and that is expandable radiallyoutward by a central portion in a direction extending along the rotationaxis X being bent. Therefore, the strut 41 and the support portion 50can be easily delivered into and are caused to expand in the body lumen,thereby enabling a proper cutting range to be secured. Furthermore,according to the medical device 10, the support portion 50 supports thestrut 41 from the radially inner side. Accordingly, excessive damage tothe biological tissues, which is caused by the edge portion of the strut41 can be reduced, and substances can be prevented from being caught inthe gap between the struts 41. Therefore, it is possible to prevent thedevice from being damaged or broken.

The strut 41 is configured so that the blade 47 for cutting thesubstances is formed at a position on the further distal side from theportion which expands most radially outward in an expansion state.Accordingly, the blade 47 is less likely to come into contact with thebiological tissues, thereby ensuring safety. The substances can beeffectively cut by pressing the strut 41 into the stenosed site S andbringing the blade 47 into contact with the substances inside the bodylumen.

In addition, the maximum expansion portion 53 in an expansion statewhich expands most radially outward from the support portion 50protrudes radially outward further than the strut 41 from a portionbetween the struts 41. Accordingly, the maximum expansion portion 53 ofthe support portion 50, which has a lower influence on the biologicaltissues than the strut 41 comes into contact with the biologicaltissues. Therefore, normal biological tissues can be prevented frombeing damaged by the edge portion of the strut 41, and thus, safety canbe improved.

In addition, in the strut 41 in an expansion state, the outer peripheralsurface having the blade 47 formed therein tilts radially inward as itgoes toward a side in the rotating direction Y. Therefore, the strut 41comes into smooth contact with a contact target from a side tiltingradially inward in the strut 41. Accordingly, excessive damage to thebiological tissues, which is caused by the strut 41 can be reduced.

In addition, the strut 41 is configured to have the wide portion 46whose width in the circumferential direction is relatively wider thanthat of an adjacent portion, and the wide portion 46 has the blade 47formed therein. Accordingly, the wide portion 46 prevents the supportportion 50 from protruding radially outward. Therefore, the blade 47 canbe favorably brought into contact with the contact target without beinghindered by the support portion 50.

The length in which the maximum expansion portion 53 in an expansionstate protrudes radially outward from the strut 41 is greater than thelength in which the support portion 50 protrudes radially outward from aportion between the struts 41 in the portion having the wide portion 46arranged therein. Accordingly, the maximum expansion portion 53 isbrought into contact with the biological tissues, thereby helpingprevent normal biological tissues from being damaged by the strut 41.Even so, the blade 47 of the strut 41 is effectively brought intocontact with the substances inside the body lumen. Accordingly, thesubstances can be favorably cut.

The strut 41 is configured to have the tilting portion 44 which tilts tothe rotation axis X in a contraction state. Accordingly, the outerperipheral surface of the strut 41 can be set to tilt at a desired angleby using an asymmetric shape of the tilting portion 44 in an expansionstate, thereby allowing a further degree of freedom in design.Therefore, the strut 41 can be set to have an angle by which thebiological tissues are less likely to be damaged and the substancesinside the body lumen can be cut relatively easily. In addition, thetilting portion 44 is disposed on the proximal side of the strut 41. Inthis manner, a portion on the proximal side of the strut 41 comes intocontact with the support portion 50 by using a wide area. Accordingly,the support portion 50 can be prevented from being misaligned with thestrut 41.

In addition, according to the present disclosure, a treatment method isdisclosed for cutting substances inside a body lumen. The treatmentmethod is adopted by using a medical device including a drive shaft thatis rotatable, at least one strut that rotatably interlocks with a distalside of the drive shaft, that extends along a rotation axis, and whosecentral portion is bent so as to be expandable radially outward, and asupport portion that is rotatably connected to the distal side of thedrive shaft, that is formed in a mesh shape and a tubular shape whileincluding multiple gaps, at least a portion of which is positioned on aradially inner side of the strut, and that is expandable radiallyoutward by a central portion in a direction extending along the rotationaxis being bent. Then, the treatment method can include (i) a step ofinserting the strut and the support portion which are in a contractionstate into the body lumen, (ii) a step of expanding the strut and thesupport portion, (iii) a step of cutting the substances inside the bodylumen by causing the drive shaft to rotate the strut and the supportportion, (iv) a step of contracting the strut and the support portion,and (v) a step of removing the strut and the support portion from theinside of the body lumen. According to the treatment method, the strutand the support portion are inserted into the body lumen so as to beeasily delivered into the body lumen, thereby helping enable a propercutting range to be secured. Furthermore, according to the treatmentmethod, the support portion supports the strut from the radially innerside, and the strut is rotated so as to cut the substances. Accordingly,excessive damage to the biological tissues, which is caused by the edgeportion of the strut can be reduced, and substances are prevented frombeing caught in the gap between the struts. Therefore, the device can beprevented from being damaged or broken.

In addition, according to the above-described treatment method, in thestep of expanding the strut and the support portion, the maximumexpansion portion, which expands most radially outward from the supportportion may protrude radially outward further than the strut from aportion between the struts. In this manner, the maximum expansionportion of the support portion, which has a lower influence on thebiological tissues than the strut comes into contact with the biologicaltissues. Accordingly, normal biological tissues can be prevented frombeing damaged by the edge portion of the strut, and thus, safety can beimproved.

In addition, the above-described treatment method may further include astep of installing the filter portion inside the body lumen before thestep of cutting the substances inside the body lumen, a step of causingthe filter portion to collect the substances inside the body lumen afterthe step of cutting the substances inside the body lumen, and a step ofremoving the filter portion from the inside of the body lumen. In thismanner, the substances (debris) which are cut and appeared by the bladeof the strut can be collected and removed by the filter portion.Accordingly, a new stenosed site or an occluded site can be preventedfrom developing in the peripheral blood vessel due to the debris flowingto the peripheral blood vessel.

Second Embodiment

In a medical device 200 according to a second embodiment of the presentdisclosure, a configuration of the cutting unit 40, the outer sheath 80,and the operation unit 90 is particularly different from that of thefirst embodiment. The same reference numerals are given to elementshaving the same function as the first embodiment, and descriptionthereof will be omitted.

As illustrated in FIG. 14, the medical device 200 according to thesecond embodiment of the present disclosure includes a treatment device210 which cuts a stenosed site or an occluded site, and the filterdevice 30 which collects debris (substance) which is cut and dropped offfrom the stenosed site or the occluded site.

As illustrated in FIGS. 14 and 15, the treatment device 210 can includea cutting unit 220 which is expandable and contractible radiallyoutward, a support portion 230 which supports the cutting unit 220, adrive shaft 240 which rotates the cutting unit 220, and a linear motionshaft 250 which adjusts a deformation amount of the cutting unit 220.Furthermore, the treatment device 210 can include a distal tube 260which interlocks with a distal side of the linear shaft 250, an outersheath 270 which can accommodate the cutting unit 220, an inner tube 280which is arranged inside the liner motion shaft 250, and an operationunit 290 which is disposed on an operating hand side for operation.Furthermore, the treatment device 210 can include a control unit 300which controls driving of the drive shaft 240, a pushing/pullingresistance measuring unit 310 (detection unit) which is attached to thedrive shaft 240, an interlock portion 320 which interlocks proximalportions of the drive haft 240 and the linear motion shaft 250 with eachother, and a notification unit 400 which gives notification that cuttingresistance exceeds a threshold value.

The cutting unit 220 can include at least one (four in the presentembodiment) strut 41 which extends along the rotation axis X of thedrive shaft 240, a tubular distal end portion 221 which is formedintegrally with the strut 41 on a distal side of each of the struts 41,and the tubular proximal fixed end 43 which is formed integrally withthe strut 41 on a proximal side of each of the struts 41. The distal endportion 221 is not fixed to the support portion 230 and the liner motionshaft 250, and is movable in the axial direction relative to the supportportion 230 and the linear motion shaft 250. The distal end portion 221comes into contact with the proximal portion of the distal tube 260interlocking with the linear motion shaft 250 by the linear motion shaft250 moving in a proximal direction with respect to the cutting unit 220(refer to FIGS. 19A and 19B).

The support portion 230 is arranged so as to support the cutting unit220 radially inward from the cutting unit 220, and is formed in atubular shape by braiding multiple wires 231 so as to have a gap 232between the wires 231. A distal end portion 234 of the support portion230 is configured so that the multiple wires 231 gather into a tubularshape, and is fixed to the outer peripheral surface of the linear motionshaft 250 without being fixed to an inner side surface of the distal endportion 221 of the cutting unit 220. A proximal end portion 235 of thesupport portion 230 is configured so that the multiple wires 231 gatherinto a tubular shape, and is fixed to an inner peripheral surface of theproximal fixed end 43 of the strut 41.

Some of the multiple wires 231 are wires configured to have an X-raycontrast material. In this manner, a position and an expansion diameterof the support portion 230 and the cutting unit 220 can be accuratelyrecognized by using X-ray fluoroscopy, thereby facilitating manualskills. For example, the X-ray contrast materials preferably includegold, platinum, platinum-iridium alloy, silver, stainless steel,molybdenum, tungsten, tantalum, palladium, an alloy thereof or the like.Instead of the support portion 230, a portion of the cutting unit 220may be configured to have the X-ray contrast material. For example, theinner peripheral surface of the cutting unit 220 may be covered with theX-ray contrast material by means of plating. In this manner, theposition and the expansion diameter of the support portion 230 and thecutting unit 220 can be accurately recognized by using X-rayfluoroscopy, thereby further facilitating manual skills.

If the distal end portion 234 and the proximal end portion 235 are movedclose to each other, the support portion 230 can shift from acontraction state (refer to FIG. 15) where the support portion 230 has atubular shape having a substantially uniform outer diameter to anexpansion state (refer to FIGS. 19A and 19B) where the support portion230 is deformed so that a central portion of the support portion 230 isbent radially outward. If the central portion of the support portion 230is bent radially outward, the distal end portion 234 gradually movesclose to the distal tube 260, and the strut 41 arranged on the outerside of the support portion 230 is pressed and expands radially outwardby the support portion 230. Until the distal tube 260 comes into contactwith the distal end portion 234, as illustrated in FIG. 19A, the distalend portion 221 is not fixed to the support portion 230 and the linearmotion shaft 250. Accordingly, a force in the axial direction hardlyacts between the distal end portion 221 and the proximal fixed end 43.The cutting unit 220 expands by only a force acting radially outwardwhich is received from the support portion 230. Therefore, a gap is lesslikely to occur between the strut 41 and the wires 231, and thus,stenosis substances or debris are not interposed between the strut 41and the wires 231. Accordingly, the strut 41 can be prevented from beingdamaged, and normal biological tissues can be prevented from beingdamaged by the edge portion of the strut 41. If the distal tube 260moving together with the linear motion shaft 250 comes into contact withthe distal end portion 221, as illustrated in FIG. 19B, the distal endportion 221 receives a force in the proximal direction from the distaltube 260, and a force of contracting the distal end portion 221 in theaxial direction acts on the distal end portion 221. In this manner, thestrut 41 expands not only by the force acting radially outward which isreceived from the support portion 230, but also by the contractionforce. Therefore, while a desirable state is maintained where a gap isless likely to occur between the strut 41 and the wires 231, the supportportion 230 can be prevented from pressing the cutting unit 220 morethan necessary.

As illustrated in FIGS. 15 and 16, the drive shaft 240 is formed in atubular shape. The distal side is fixed to the proximal fixed end 43 ofthe cutting unit 220, and the driven gear 61 is fixed to the proximalside. Multiple hole portions 241 through which a fluid can be circulatedare formed to penetrate the outer peripheral surface from the innerperipheral surface in at least a portion of the drive shaft 240. Aportion of the outer peripheral surface of the proximal portion of thedrive shaft 240 is covered with a cover portion 242 for decreasing africtional force by coming into slidable contact with a first sealingportion 355 inside the operation unit 290.

A configuration material of the cover portion 242 is preferably lowfriction material, and is a fluorine-based resin material such aspolytetrafluoroethylene (PTFE) or the like. As illustrated in FIG. 17,the hole portions 241 of the drive shaft 240 may be configured to serveas multiple through-holes disposed in the tubular body. Alternatively,as illustrated in FIG. 18, the hole portions 241 may be configured toinclude a gap formed from a braided body of braided wires 243. Inaddition, the drive shaft 240 may be configured to include coils so thatthe hole portions 241 are gaps of the coils. The hole portions 241 maybe entirely or partially formed in the drive shaft 240. When the driveshaft 240 in which the hole portions 241 are disposed in a predeterminedrange is formed by using the braided body or the coils, the braided bodyor the coils which have gaps are partially covered with a material suchas a resin or the like. In this manner, the drive shaft 240 can beeasily formed.

As illustrated in FIGS. 15 and 16, the linear motion shaft 250 is atubular body which can move in the direction of the rotation axis Xrelative to the drive shaft 240 in order to expand and contract thecutting unit 220 and the support portion 230. The linear motion shaft250 penetrates the drive shaft 240, the cutting unit 220, and thesupport portion 230. In the linear motion shaft 250, a distal side ofthe linear motion shaft 250 is fixed to the distal end portion 234 ofthe wire 231, and a proximal side of the distal end portion 234 isconnected to a moving mechanism 340, which linearly moves the linearmotion shaft 250 along the rotation axis X. The proximal side of thelinear motion shaft 250 further protrudes to the proximal side from thedrive shaft 240. Multiple hole portions 251 through which a fluid can becirculated are formed to penetrate the outer peripheral surface from theinner peripheral surface in at least a portion of the linear motionshaft 250. Similarly to the hole portions 241 of the drive shaft 240,the hole portions 251 of the linear motion shaft 250 may be configuredto serve as multiple through-holes disposed in the tubular body.Alternatively, the hole portions 251 may be configured to include gapsof a threaded body or coils.

The interlock portion 320 is a tubular expandable and contractiblemember which interlocks with the proximal portion of the linear motionshaft 250 and the proximal portion of the drive shaft 240 to each other,and a diameter of the interlock portion 320 decreases in a tapered shapein the proximal direction. The interlock portion 320 interlocks with thelinear motion shaft 250 and the drive shaft 240 in a liquid-tightmanner. The interlock portion 320 maintains liquid-tightness between thelinear motion shaft 250 and the drive shaft 240 in the operation unit290, and allows the linear motion shaft 250 to move to the drive shaft240 in the axial direction. The linear motion shaft 250 and the driveshaft 240 which are relatively moved interlock with each other by theexpandable and contractible interlock portion 320. Accordingly, it isnot necessary to employ a sealing structure such as an O-ring or thelike which causes friction. Without losing the driving force, theliquid-tightness between the linear motion shaft 250 and the drive shaft240 can be maintained. In addition, the interlock portion 320 istwisted, thereby enabling the linear motion shaft 250 and the driveshaft 240 to be aligned with each other in the rotating direction.

A configuration material of the interlock portion 320 is notparticularly limited as long as the material is expandable andcontractible. However, for example, various rubber materials such asnatural rubber, isoprene rubber, butadiene rubber, chloroprene rubber,silicone rubber, fluorine rubber, styrene-butadiene rubber and the like;various thermoplastic elastomers such as styrene-based,polyolefin-based, polyurethane-based, polyester-based, polyamide-based,polybutadiene-based, trans-polyisoprene-based, fluororubber-based,chlorinated polyethylene-based elastomers, and the like; or the like canbe preferably used.

The outer sheath 270 is a tubular body for covering the outer side ofthe drive shaft 240, and is movable in the direction extending along therotation axis X. The outer sheath 270 is operable by gripping theproximal portion. The outer sheath 270 can internally accommodate thecutting unit 220 and the support portion 230 in a contraction state bybeing moved to the distal side. The cutting unit 220 and the supportportion 230 can be exposed outward by moving the outer sheath 270 to theproximal side.

The inner tube 280 is arranged inside the linear motion shaft 250, andis a tubular body which internally has a lumen 281 into which the filterdevice 30, a guidewire, or the like can be inserted. The inner tube 280is movable to the linear motion shaft 250 in the direction extendingalong the rotating direction X. Multiple hole portions 282 through whicha fluid can be circulated are formed to penetrate the outer peripheralsurface from the inner peripheral surface in at least a portion of theinner tube 280. Similarly to the hole portions 241 of the drive shaft240, the hole portions 282 of the inner tube 280 may be configured toserve as multiple through-holes disposed in the tubular body.Alternatively, the hole portions 282 may be configured to include gapsof a threaded body or coils.

The distal tube 260 is fixed to the distal side of the linear motionshaft 250. The inner tube 280 is arranged inside the distal tube 260.Multiple convex portions 261 can be formed on the outer peripheralsurface of the distal tube 260. For example, the convex portions 261 canbe formed by means of embossing, or can be formed by disposing multipleholes. Alternatively, the convex portions 261 can be formed by attachingfine metal powder or the like to the surface of the distal tube 260, orcan be formed by mixing the material of the distal tube 260 with thefine metal powder or the like. For example, as the material of the metalpowder, stainless steel or the like can be preferably used.

As illustrated in FIG. 14, the pushing/pulling resistance measuring unit310 (detection unit) can include a sensor 311 for detectingpushing/pulling resistance (resistance in the axial direction) acting onthe drive shaft 240 when the cutting unit 220 and the support portion230 are pushed to and pulled out from a stenosed site, and a measuringdevice 312 which calculates the pushing/pulling resistance by receivinga signal from the sensor 311. For example, the sensor 311 is a straingauge attached in the vicinity of a first bearing portion 331 whichreceives the pushing/pulling resistance. The measuring device 312 cancalculate the pushing/pulling resistance, based on the signal receivedfrom the sensor 311, and transmits the result to the control unit 300. Aportion to which the sensor 311 is attached is not particularly limitedas long as the pushing/pulling resistance of the drive shaft 240 can bedetected.

As illustrated in FIGS. 14 and 16, the operation unit 290 includes adrive mechanism 330 which provides the drive shaft 240 with a rotatingforce, a moving mechanism 340 which moves the linear motion shaft 250along the rotation axis X, and a liquid supply unit 350 which supplies aphysiological salt solution or the like into the outer sheath 270.

The liquid supply unit 350 can include a first housing 351 to which theouter sheath 270 is fitted, a container bag 352 which contains thephysiological slat solution, a pressurizing bag 353 for pressurizing thecontainer bag 352, a connection tube 354 which connects the containerbag 352 and the first housing 351 to each other, a first sealing portion355 which is arranged inside the first housing 351, and a fixing portion358 for fixing the first sealing portion 355.

The first housing 351 is a tubular member, and is movable to a secondhousing 333 in the axial direction while a second cam portion 356 whichis slidably fitted to a second cam groove 335 formed in the secondhousing 333 in which the motor 96 is accommodated is formed on the outerperipheral surface of the first housing 351. The outer sheath 270 isfitted and fixed to the first housing 351 from the distal side. Forexample, the first sealing portion 355 is an O-ring or an X-ring, isarranged inside the proximal portion of the first housing 351, and comesinto slidable contact with the cover portion 242 on the outer peripheralsurface of the drive shaft 240 entering the inside of the first housing351 after passing through the inside of the outer sheath 270. The firstsealing portion 355 is fixed by the fixing portion 358 twisted into thefirst housing 351 from the proximal side. The first sealing portion 355allows the drive shaft 240 to rotate and to move in the axial direction,and maintains liquid-tightness between the drive haft 240 and the firsthousing 351.

In addition, a port portion 357 to which the connection tube 354extending from the container bag 352 is connected is formed in the firsthousing 351. The physiological salt solution supplied from the containerbag 352 can flow into the first housing 351 through the port portion357. The pressurized physiological salt solution flowing into the firsthousing 351 can flow into the outer sheath 270 on the distal side, sincethe flow to the proximal side is regulated by the first sealing portion355.

The drive mechanism 330 can include the drive gear 94 which meshes withthe driven gear 61, the motor 96 which serves as a drive sourceincluding the rotary shaft 95 to which the drive gear 94 is fixed, thecontrol unit 300 which controls current supply to the motor 96, and thefirst bearing portion 331 and the second bearing portion 332 whichrotatably support the linear motion shaft 250. Furthermore, the drivemechanism 330 includes the second housing 333 which accommodates themotor 96, and a frame body 334 which interlocks with the second housing333 and which holds the first bearing portion 331 and the second bearingportion 332.

As described above, the second housing 333 is a box-shaped member whichaccommodates the motor 96. The second cam groove 335 to which the secondcam portion 356 of the first housing 351 is slidably fitted is formed onan outer surface of the second housing 333.

The frame body 334 can include a first partition wall 336 and a secondpartition wall 337 which are parallel to each other. The second housing333 is fixed to the first partition wall 336 on the distal side, and themoving mechanism 340 is fixed to the second partition wall 337 on theproximal side.

The rotary shaft 95 extending from the motor 96 inside the secondhousing 333 penetrates the first partition wall 336, and the drive gear94 is arranged between the first partition wall 336 and the secondpartition wall 337. In addition, the first bearing portion 331 isarranged on the first partition wall 336, and the drive shaft 240extending from the first housing 351 is rotatably held by the firstbearing portion 331. The driven gear 61 fixed to the drive shaft 240 islocated between the first partition wall 336 and the second partitionwall 337, and meshes with the drive gear 94. The second bearing portion332 which rotatably supports the drive shaft 240 is arranged on thesecond partition wall 337.

If power is supplied to the motor 96 via a cable 301 and the rotaryshaft 95 of the motor 96 is rotated, the driven gear 61 meshing with thedrive gear 94 is rotated, and the drive shaft 240 supported by the firstbearing portion 331 and the second bearing portion 332 is rotated. Ifthe drive shaft 240 is rotated, the cutting unit 220, the supportportion 230, and the distal tube 260 which are fixed to the distal sideof the drive shaft 240 are rotated. The distal end portion 234 of thesupport portion 230 is joined to the linear motion shaft 250.Accordingly, if the support portion 230 is rotated, the linear motionshaft 250 is also rotated so as to follow the support portion 230.

As illustrated in FIGS. 14, 16, and 19, the moving mechanism 340 caninclude a dial 360 which can be rotated by an operator's finger, amoving base 370 which is linearly movable by rotating the dial 360, athird bearing portion 341 which is fixed to the moving base 370 andwhich rotatably supports the linear motion shaft 250, a second sealingportion 342, and a proximal fixing portion 380 which fixes the secondsealing portion 342. Furthermore, the moving mechanism 340 can include athird housing 390, which can accommodate the moving base 370. A firstcam groove 391 to which a first cam portion 371 formed to protrude inthe moving base 370 is slidably fitted is formed on an inner surface ofthe third housing 390.

The dial 360 is a cylindrical member arranged on the proximal side ofthe frame body 334, and is rotatable by operating the outer peripheralsurface with a finger. In the dial 360, a portion of the distal endportion is located inside the third housing 390. A groove portion 362extending in the circumferential direction is formed on the outerperipheral surface of the dial 360. A hook portion 392 formed in theproximal portion of the third housing 390 is fitted to the grooveportion 362, thereby restricting the movement of the dial 360 in theaxial direction. The dial 360 is held so as to be rotatable with respectto the third housing 390. A feed screw 361 screwed to a screw groove 372formed in the moving base 370 is formed on an inner peripheral surfaceof the dial 360. A discharge hole 366 for discharging internal airduring priming is formed in the dial 360. The discharge hole 366 can beopened and closed by a stopper 367.

The moving base 370 has the first cam portion 371 fitted to the firstcam groove 391 of the third housing 390, and the screw groove 372 towhich the feed screw 361 is screwed. Therefore, if the feed screw 361 isrotated, the moving base 370 is not rotatable with respect to the thirdhousing 390, and is linearly movable along the rotation axis X. Thethird bearing portion 341, which is fixed to the moving base 370 appliesa moving force to the linear motion shaft 250 in response to themovement of the moving base 370. Accordingly, it is preferable to use abearing which can receive force acting in the axial direction (thrustforce). Another sealing member may be disposed on the proximal side ofthe third bearing portion 341.

The second sealing portion 342 can be accommodated in a concave portion364 formed so as to surround a through-hole 363 through which the linearmotion shaft 250 of the dial 360 penetrates on the proximal side of thedial 360. The second sealing portion 342 is an annular member, whichcomes into contact with the outer peripheral surface of the proximalportion of the linear motion shaft 250 located inside of the secondsealing portion 342.

The proximal fixing portion 380 can be a bolt-shaped member which can betwisted so as to be screwed to the screw groove 365 formed in theconcave portion 364 of the dial 360. The proximal fixing portion 380internally has a through-hole 381 in which the inner tube 280 isarranged. The proximal fixing portion 380 is twisted into the concaveportion 364 of the dial 360, thereby deforming the second sealingportion 342 and pressing the inner tube 280. In this manner, theproximal fixing portion 380 maintains a liquid-tight state between thedial 360 and the inner tube 280, and holds the inner tube 280.

The control unit 300 supplies a current to the motor 96 via the cable301, functions as a detection unit which detects a change in thesupplied current, and can detect cutting resistance (resistance in therotating direction) in the cutting unit 220 which is rotatably driven bythe motor 96. In addition, from the measuring device 312, the controlunit 300 receives a measured result of pushing/pulling resistance(resistance in the axial direction) acting on the drive shaft 240. Ifthe cutting resistance exceeds a preset threshold value, the controlunit 300 stops the rotation of the motor 96, and causes the notificationunit 400 to display that the cutting resistance exceeds the thresholdvalue. When the cutting resistance exceeds the threshold value, thecontrol unit 300 may decelerate the rotation speed, instead of stoppingthe rotation of the motor 96. Furthermore, when the pushing/pullingresistance exceeds a preset threshold value, the control unit 300 stopsthe rotation of the motor 96, and causes the notification unit 400 todisplay that the cutting resistance exceeds the threshold value. Whenthe pushing/pulling resistance exceeds the threshold value, the controlunit 300 may decelerate the rotation speed, instead of stopping therotation of the motor 96.

The notification unit 400 can include a monitor 401 and a speaker 402which are connected to the control unit 300 so as to be communicabletherebetween. The monitor 401 notifies an operator by displaying thatthe cutting resistance or the pushing/pulling resistance exceeds thethreshold value. The speaker 402 uses sound in order to notify theoperator of the fact that the cutting resistance or the pushing/pullingresistance exceeds the threshold value. When the cutting resistance orthe pushing/pulling resistance exceeds the threshold value, the controlunit 300 may not stop the rotation of the motor 96, and may cause thenotification unit 400 only to issue a notification to the operator. Inthis case, the operator receives the notification from the notificationunit 400 visibly or audibly. In this manner, the operator can stop themotor 96, can stop pushing or pulling, or can change a diameter of thecutting unit 220 by rotating the dial 360.

Next, a method of using the medical device 200 according to the secondembodiment will be described by exemplifying a case where stenosissubstances inside the blood vessel are cut. A method used until thefilter instrument 110 is installed is the same as the method describedin the first embodiment.

First, similarly to the method described in the first embodiment, anintroducer sheath (not illustrated) is percutaneously inserted into theblood vessel on a further upstream side (proximal side) from thestenosed site S in the blood vessel. The guidewire 130 is inserted intothe blood vessel, and is caused to reach the proximal side of thestenosed site S via the introducer sheath. Thereafter, as illustrated inFIG. 8B, the guiding catheter 140 is inserted into the blood vesselalong the guidewire 130 so as to reach the proximal side of the stenosedsite S.

Next, the support catheter 150 is pushed to move forward to the proximalside of the stenosed site S along the guidewire 130. Thereafter, asillustrated in FIG. 9A, the support catheter 150 and the guidewire 130are caused to reach the further distal side from the stenosed site S.Thereafter, the guidewire 130 is removed therefrom in a state where thesupport catheter 150 remains inside the blood vessel.

Then, the filter device 30 in which the filter instrument 110 isaccommodated inside the sheath 120 is prepared. The filter portion 111is arranged at a position close to the distal end portion of the tubularbody 121 of the sheath 120, and a shape of the filter portion 111 isrestricted to a contraction state. Then, as illustrated in FIG. 9B, thefilter device 30 is inserted into the blood vessel via the supportcatheter 150 so as to reach the further distal side from the stenosedsite S. Thereafter, the support catheter 150 is removed therefrom.

Next, the sheath 120 is moved to the proximal side relative to thefilter instrument 110 so that the filter portion 111 protrudes to thedistal side from the tubular body 121. In this manner, as illustrated inFIG. 10A, the filter portion 111 is brought into an expansion state byusing its own restoring force. An outer peripheral portion of the filterportion 111 which is shaped into a cage comes into contact with an innerwall surface of the blood vessel. At this time, the filter portion 111is open toward the stenosed site S on the upstream side (proximal side).Thereafter, the sheath 120 is removed therefrom by leaving the filterinstrument 110 behind.

Next, the treatment device 210 in a state where the cutting unit 220 andthe support portion 230 contracts and are accommodated inside the outersheath 270 is prepared. The container bag 352 is pressurized by thepressurizing bag 353, and a physiological salt solution is supplied intothe first housing 351 from the container bag 352 via the connection tube354. As illustrated in FIG. 21, the physiological salt solution flowinginto the first housing 351 moves in the distal direction through theinside of the outer sheath 270, since the movement in the proximaldirection is restricted by the first sealing portion 355. If thephysiological salt solution flowing into the outer sheath 270 reaches aregion where the hole portion 241 of the drive shaft 240 is formed, aportion of the physiological salt solution passes through the holeportion 241, and flows into the drive shaft 240. If the physiologicalsalt solution flowing into the drive shaft 240 reaches a region wherethe hole portion 251 of the linear motion shaft 250 is formed, a portionof the physiological salt solution passes through the hole portion 251,and flows into the linear motion shaft 250. If the physiological saltsolution flowing into the linear motion shaft 250 reaches a region wherethe hole portion 282 of the inner tube 280 is formed, a portion of thephysiological salt solution passes through the hole portion 282, andflows into the lumen 281 of the inner tube 280.

Then, as illustrated in FIG. 22, the physiological salt solution flowinginto the outer sheath 270, into the drive shaft 240, into the linearmotion shaft 250, and into the inner tube 280 is discharged from theouter sheath 270, the drive shaft 240, the linear motion shaft 250, andthe opening portion on the distal side of the inner tube 280.Furthermore, as illustrated in FIG. 23, the movement of thephysiological salt solution flowing into the drive shaft 240 isrestricted by the interlock portion 320 interlocking with the proximalportion of the drive shaft 240 and the linear motion shaft 250. Thephysiological salt solution flowing into the linear motion shaft 250flows in the proximal direction, passes through the inside of the movingbase 370, and flows into the dial 360. The physiological salt solutionflowing into the dial 360 is discharged outward through the dischargehole 366. After the air inside the moving base 370 and the air insidethe dial 360 are discharged, the stopper 367 can close the dischargehole 366. The physiological salt solution flowing into the inner tube280 flows in the proximal direction, and is discharged outward from theopening portion on the proximal side. In this manner, priming iscompleted. Even after the priming is completed, liquid is continuouslysupplied from the container bag 352 until manual skills using thetreatment device 210 are finished. In addition, the priming of thetreatment device 210 may be performed without using the pressurizing bag353.

Next, the proximal end portion of the shaft portion 113 is inserted intothe distal side opening portion of the inner tube 280. As illustrated inFIG. 24A, the distal end portion of the treatment device 210 is causedto reach the inside of the blood vessel via the guiding catheter 140.Then, the distal end portion of the treatment device 210 is located onthe proximal side of the stenosed site S by using X-ray fluoroscopy.Since the physiological salt solution is always supplied to thetreatment device 210 by the container bag 352, the blood is preventedfrom flowing into the outer sheath 270, the drive shaft 240, the linearmotion shaft 250, and the inner tube 280.

Next, if the first housing 351 is moved to the proximal side withrespect to the second housing 333 as illustrated in FIG. 25, the outersheath 270 is moved to the proximal side as illustrated in FIG. 24B, andthe cutting unit 220 and the support portion 230 are exposed inside theblood vessel. This state indicates a state where the cutting unit 220and the support portion 230 contract on the further proximal side fromthe stenosed site S.

Next, a gap size of the stenosed site S is detected by using the X-rayfluoroscopy. The gap size of the stenosed site S can be detected byviewing the gap size from X-ray imaged video, or can be detected bycomparing a gap of the stenosed site S in the X-ray imaged video with adimension-recognizable portion of the treatment device 210, for example(for example, the strut 41 or the support portion 230). In addition, thegap size of the stenosed site S can be detected in more detail byutilizing intravascular ultrasound (IVUS), optical coherence tomography(OCT), or optical frequency domain imaging (OFDI).

Thereafter, as illustrated in FIG. 25, if the dial 360 is rotated, thefeed screw 361 is rotated, the moving base 370 is moved to the proximalside, and the linear motion shaft 250 interlocking with the moving base370 is moved to the proximal side with respect to the drive shaft 240.If the linear motion shaft 250 is moved to the proximal side, the distalend portion 234 and the proximal end portion 235 move close to eachother. As illustrated in FIGS. 20A, 20B, and 26A, the central portion ofthe support portion 230 is deformed so as to be bent radially outward,and is brought into an expansion state. If the central portion of thesupport portion 230 is bent radially outward, the strut 41 arranged onthe radially outer side of the support portion 230 is pressed andexpands radially outward by the support portion 230. In this case, atleast when the expansion starts, the distal end portion 221 of thecutting unit 220 is not fixed to the support portion 230 and the linearmotion shaft 250. Accordingly, force acting in the axial direction doesnot act between the distal end portion 221 and the proximal fixed end43. As illustrated in FIG. 20A, the cutting unit 220 is caused to expandby only force acting radially outward which is received from the supportportion 230. Therefore, a gap is less likely to occur between the strut41 and the wires 231. If the linear motion shaft 250 is moved to theproximal side with respect to the drive shaft 240, as illustrated inFIG. 25, the interlock portion 320 which interlocks the proximal portionof the linear motion shaft 250 and the proximal portion of the driveshaft 240 with each other is extended, thereby maintaining aliquid-tight state. Accordingly, the physiological salt solution flowinginto a portion between the linear motion shaft 250 and the drive shaft240 does not leak out therefrom.

Then, the size of the cutting unit 220 and the support portion 230 canbe optionally adjusted by using a rotation amount of the dial 360.Therefore, the cutting unit 220 can optionally adjust the size duringthe expansion to a desirable size, and thus can perform effectivecutting.

When the dial 360 is rotated so as to expand the support portion 230 andthe cutting unit 220, the X-ray fluoroscopy is used in order to expandthe expansion diameter of the cutting unit 220 to be larger than the gapof the stenosed site S while the expansion diameter of the cutting unit220 is compared with the gap of the stenosed site S. In this case, theouter diameter of the portion which expands most in the cutting unit 220and the support portion 230 has a size between the minimum contractionstate where both of these contract most and the maximum expansion statewhere both of these expand most.

Next, if the control unit 300 rotates the motor 96 by supplying thecurrent to the motor 96, the driving force of the motor 96 istransmitted to the driven gear 61 from the drive gear 94, the driveshaft 240 interlocking with the driven gear 61 is rotated, and thecutting unit 220 and the support portion 230 which interlock with thedrive shaft 240 are rotated. If the cutting unit 220 and the supportportion 230 are rotated, the linear motion shaft 250 interlocking withthe support portion 230 on the distal side is also rotated. In addition,the linear motion shaft 250 interlocks with the drive shaft 240 by theinterlock portion 320 on the proximal side. Accordingly, the linearmotion shaft 250 also receives the rotating force from the proximalside. Therefore, the linear motion shaft 250 becomes likely to rotate tofollow the drive shaft 240 without any delay, and thus the linear motionshaft 250 can be prevented from being twisted. Then, the linear motionshaft 250 can be prevented from being twisted, it is not necessary tocarry out work for twisting the linear motion shaft 250. The drivingforce can be effectively transmitted to the linear motion shaft 250,thereby enabling low torque driving. In addition, since the interlockportion 320 is located outside a body when manual skills are used,safety can be ensured even if the interlock portion 320 is damaged.

Since the drive shaft 240 is rotatably supported by the first bearingportion 331 and the second bearing portion 332, the drive shaft 240 canrotate smoothly. The first sealing portion 355 is in contact with thecover portion 242 disposed on the outer peripheral surface of the driveshaft 240 inside the first housing 351, and the drive shaft 240 isrotated so as to cause the cover portion 242 to slide on the firstsealing portion 355. However, since the cover portion 242 is formed byusing a low frictional material, the rotation of the drive shaft 240 ishardly hindered. In addition, the linear motion shaft 250 can rotatesmoothly since the proximal portion is rotatably supported by the thirdbearing portion 341.

Next, in a state where the cutting unit 220 and the support portion 230are rotated, as illustrated in FIG. 26B, the treatment device 210 ispushed to move forward. In this manner, the blade 47 formed in thecutting unit 220 and the convex portion 261 (refer to FIG. 22) formed inthe distal tube 260 come into contact with the stenosed site S so as tocut stenosis substances. The debris D changed from the stenosissubstances flows to the distal side (downstream side). The debris Dflowing to the distal side enters the inside of the filter portion 111located on the distal side, and is filtered and collected by the filterportion 111. In this manner, the debris D can be prevented from flowingto the peripheral blood vessel. Accordingly, a new stenosed site can beprevented from developing in the peripheral blood vessel.

Then, when the stenosed site S is cut, the support portion 230 protrudesradially outward between the struts 41. Accordingly, the support portion230 having a lower influence on biological tissues than the strut 41comes into contact with the biological tissues. Therefore, normalbiological tissues can be prevented from being damaged by the edgeportion of the strut 41, and thus, safety can be improved.

In addition, the distal end portion 221 of the cutting unit 220 is notfixed to the support portion 230 and the linear motion shaft 250, andwhen the expansion starts, the cutting portion 220 expands by using theforce acting radially outward which is received from the support portion230. Accordingly, a gap is less likely to occur between the strut 41 andthe wires 231. In this manner, the dropped hard debris D or stenosissubstances are less likely to be interposed between the strut 41 and thewires 231. Therefore, since the strut 41 is not rolled up outward, thestrut 41 can be prevented from being damaged or broken, and thus, normalbiological tissues can be prevented from being damaged by the edgeportion of the strut 41.

When the treatment device 210 is pushed to move forward, the treatmentdevice 210 can be pulled out, after the stenosed site S is cut bypushing the cutting unit 220 to move forward, and before the cuttingunit 220 completely passes the stenosed site S. Then, the cutting unit220 is pushed gradually move forward to the stenosed site S byrepeatedly pushing and pulling the treatment device 210, therebyenabling the stenosed site S to be cut little by little. In this manner,the cutting unit 220 can be prevented from being damaged or broken bypreventing excessive force from acting on the cutting unit 220.

If excessive cutting resistance (resistance in the rotating direction)acts on the cutting unit 220, a change occurs in the current for drivingthe motor 96. The control unit 300 detects this change in the current.The control unit 300 specifies the cutting resistance based on thedetected current. When the cutting resistance exceeds a preset thresholdvalue, the control unit 300 stops the rotation of the motor 96. Then,the control unit 300 causes the monitor 401 to display that the cuttingresistance exceeds the threshold value, and causes the speaker 402 toissue the notification by using sound.

In addition, if excessive pushing/pulling resistance (resistance in theaxial direction) acts on the cutting unit 220, the excessivepushing/pulling resistance is detected by the pushing/pulling resistancemeasuring unit 310, and is notified to the control unit 300. When thepushing/pulling resistance exceeds a preset threshold value, the controlunit 300 stops the rotation of the motor 96. Then, the control unit 300causes the monitor 401 to display that the pushing/pulling resistanceexceeds the threshold value, and causes the speaker 402 to issue thenotification by using sound.

If the control unit 300 stops the motor 96 when detecting the excessivecutting resistance or pushing/pulling resistance occurring in thecutting unit 220, the control unit 300 can cause the cutting unit 220 tostop cutting before the cutting unit 220 is damaged or broken. After therotation of the motor 96 is stopped, as illustrated in FIG. 27A, thetreatment device 210 is pulled out therefrom, and the control unit 300is operated so as to rotate the motor 96 again, thereby enabling thetreatment device 210 to restart the cutting. When the cutting resistanceor the pushing/pulling resistance exceeds the threshold value, thecontrol unit 300 may decelerate the rotation speed instead of stoppingthe rotation of the motor 96. In addition, without stopping the rotationof the motor 96, the control unit 300 may cause the notification unit400 to prompt a user to stop the motor 96.

As illustrated in FIG. 27B, after the cutting unit 220 passes thestenosed site S, the treatment device 210 is pulled out therefrom. Asillustrated in FIG. 28A, the cutting unit 220 is moved to the proximalside of the stenosed site S, and the rotation of the drive shaft 240 isstopped. Next, the dial 360 is rotated again, and as illustrated in FIG.28B, the cutting unit 220 is caused to expand further. Then, similarlyto the above-described operation, the cutting unit 220 is rotated, andthe treatment device 210 is repeatedly pushed and pulled. When thecutting resistance or the pushing/pulling resistance exceeds thethreshold value, the control unit 300 stops the rotation. As illustratedin FIGS. 29A and 29B, the stenosed site S is cut little by little. Afterthe cutting unit 220 passes the stenosed site S, the treatment device210 is pulled out therefrom, the cutting unit 220 is moved to theproximal side of the stenosed site S, and the rotation of the driveshaft 240 is stopped. Then, the cutting unit 220 is caused to graduallyexpand, and the cutting unit 220 is repeatedly pushed to and pulled outfrom the stenosed site S so as to cut the stenosed site S. As describedabove, the stenosed site S is cut while the cutting unit 220 is causedto gradually expand. In this manner, the cutting unit 220 can beprevented from being damaged or broken by preventing the excessive forcefrom acting on the cutting unit 220.

After the stenosed site S is completely cut by the cutting unit 220, thedial 360 is reversely rotated as compared to when the cutting unit 220and the support portion 230 expand. In this manner, as illustrated inFIG. 16, the feed screw 361 is rotated, the moving base 370 is moved tothe distal side, and the linear motion shaft 250 interlocking with themoving base 370 is moved to the distal side. If the linear motion shaft250 is moved to the distal side, as illustrated in FIG. 15, the distalend portion 234 of the support portion 230 moves so as to be separatedfrom the proximal end portion 235, thereby bringing the cutting unit 220and the support portion 230 into a state of contracting radially inward.Next, if the first housing 351 is moved to the distal side with respectto the second housing 333, the outer sheath 270 is moved to the distalside. As illustrated in FIG. 30A, the cutting unit 220 and the supportportion 230 are accommodated inside the outer sheath 270. Thereafter,the treatment device 210 is removed outward from a body via the guidingcatheter 140.

Thereafter, as illustrated in FIG. 30B, the sheath 120 is inserted intothe blood vessel via the guiding catheter 140, and the debris D insidethe filter portion 111 is aspirated into the sheath 120. Then, thefilter portion 111 is accommodated inside the sheath 120. Thereafter,the filter instrument 110 is removed therefrom together with the sheath120. The guiding catheter 140 and the introducer sheath are removedtherefrom, thereby finishing manual skills.

Then, while the manual skills are used, the treatment device 210prevents the blood from flowing into the outer sheath 270, the driveshaft 240, the linear motion shaft 250, and the inner tube 280, sincethe physiological salt solution is always supplied to the treatmentdevice 210 by the container bag 352. Accordingly, the blood is preventedfrom coagulating inside the treatment device 210. Therefore, operabilityof the treatment device 210 can be prevented from becoming poor due tocoagulation of the blood. It is also possible to prevent coagulatedsubstances from flowing into the blood vessel, thereby improving safety.In addition, since the blood can be prevented from flowing outward viathe treatment device 210, the safety can be improved.

As described above, the medical device 200 according to the secondembodiment is configured so that the drive shaft 240 is a tubular body,and further has the linear motion shaft 250 which is arranged inside thedrive shaft 240, which is movable in the axial direction relative to thedrive shaft 240, and which is rotatable together with the drive shaft240. Then, the support portion 230 is expandable radially outward byreceiving the force acting in the axial direction, which is generated bythe relative movement of the drive shaft 240 and the linear motion shaft250 in the axial direction. In the strut 41, the movement of the distalside in the axial direction with respect to the drive shaft 240 and thelinear motion shaft 250 is not restricted. The strut 41 expands radiallyoutward by being pressed due to the radially outward expansion of thesupport portion 230. Therefore, when the strut 41 is caused to expand, agap is less likely to occur between the strut 41 and the support portion230, and the stenosis substances or the debris are less likely to beinterposed between the strut 41 and the support portion 230.Accordingly, the medical device 200 can prevent the strut 41 from beingdamaged, and can prevent normal biological tissues from being damaged bythe edge portion of the strut 41.

In addition, the medical device 200 further has the inner tube 280 whichis a tubular body arranged inside the drive shaft 240, and whoserotation is not restricted with respect to the drive shaft 240 and thelinear motion shaft 250. Therefore, according to the medical device 200,even when the drive shaft 240 and the linear motion shaft 250 arerotated, the inner tube 280 is not rotated, and the rotating force doesnot act on the filter instrument 110 inserted into the inner tube 280 orthe guidewire. For example, if the filter instrument 110 or theguidewire is directly inserted into a rotating tubular body, the filterinstrument 110 or the guidewire slides on the inner wall surface of thetubular body, thereby causing abrasion, or causing a possibility thatthe rotated filter instrument 110 or the rotated guidewire may be lesslikely to be removed. In contrast, according to the medical device 200,the filter instrument 110 or the guidewire can be inserted into theinner tube 280, which is not rotated. Accordingly, the abrasion of thefilter instrument 110 or the guidewire can be prevented, and the rotatedfilter instrument 110 or the rotated guidewire can be prevented frombecoming less likely to be removed. In addition, if the tubular body isrotated, a fluid such as the blood or the like is likely to be drawninto the tubular body. However, since the inner tube 280 is not rotated,the blood is less likely to be drawn into the lumen 281 of the innertube 280. Accordingly, it is possible to prevent operability frombecoming poor by preventing the blood from coagulating inside the lumen281. In addition, if the tubular body into which the filter instrument110, the guidewire or the like is inserted is rotated, abrasion with theinner wall surface of the tubular body causes the filter instrument 110,the guidewire or the like to move in the axial direction. Consequently,in some cases, there is a possibility that the blood vessel may bedamaged. However, according to the medical device 200, the inner tube280 into which the filter instrument 110, the guidewire or the like isinserted is not rotated. Therefore, the blood vessel can be preventedfrom being damaged due to the movement of the filter instrument 110, theguidewire or the like in the axial direction.

In addition, according to the medical device 200, a portion of the strut41 or the support portion 230 has the contrast portion configured toinclude an X-ray contrast material. Accordingly, the position or theexpansion diameter of the strut 41 or the support portion 230 can beaccurately recognized by using X-ray fluoroscopy, thereby furtherfacilitating manual skills.

In addition, the medical device 200 further has the distal tube 260which has a tubular shape and in which the multiple convex portions 261are formed on the outer peripheral surface, on the further distal sidefrom the strut 41. Accordingly, the distal tube 260 can also cut thestenosed site S, thereby enabling the stenosed site S to be cut quickly.

In addition, a treatment method (therapy method) is disclosed forcutting substances inside a body lumen. The treatment method is adoptedby using a medical device including a drive shaft that is rotatable, atleast one strut that rotatably interlocks with a distal side of thedrive shaft, that extends along a rotation axis, and whose centralportion is bent so as to be expandable radially outward, and a supportportion that is rotatably driven by the drive shaft, that is formed in amesh shape and a tubular shape while including multiple gaps, at least aportion of which is positioned on a radially inner side of the strut,and that is expandable radially outward by a central portion in adirection extending along the rotation axis being bent. The treatmentmethod can include (i) a step of inserting the strut and the supportportion which are in a contracted state into the body lumen, (ii) a stepof detecting a size of a gap between the substances inside the bodylumen, (iii) a step of expanding the strut and the support portion so asto be larger than the gap in the stenosed site on a further proximalside from the gap in the stenosed site, (iv) a step of cutting thestenosis substances by causing the drive shaft to rotate the strut andthe support portion so as to be pressed into the gap in the stenosedsite, (v) a step of contracting the strut and the support portion, and(vi) a step of removing the strut and the support portion from theinside of the body lumen. According to the treatment method configuredas described above, it is possible to cut substances in a stenosed siteafter the strut and the support portion are caused to expand on thefurther proximal side from the stenosed site so as to have a suitablesize which is larger than the gap in the stenosed site. Accordingly, thesubstances in the stenosed site can be effectively cut. The meaning ofthe stenosed site also includes an occluded site, and the occluded siteis one form of the stenosed site.

In addition, according to the above-described treatment method, the stepof expanding the strut and the support portion and the step of cuttingthe substances in the stenosed site may be repeated at least once whilethe strut and the support portion are caused to gradually expand. Inthis manner, the substances in the stenosed site can be cut little bylittle, thereby reducing load acting on the strut. Accordingly, thesubstances can be more reliably cut while the strut is prevented frombeing damaged or broken.

In addition, according to the above-described treatment method, in thestep of expanding the strut and the support portion, the strut and thesupport portion may be caused to expand so as to have a size smallerthan that in the maximum expansion state. For example, when the stenosedsite is dilated by using a balloon, the balloon is brought into thepreset maximum expansion state so as to dilate the stenosed site.However, according to this treatment method, the strut having a sizesmaller than that in the maximum expansion state can cut the substancesin the stenosed site. Accordingly, it is easy to set desirable cuttingconditions.

In addition, according to the above-described treatment method, in thestep of detecting a gap size of the stenosed site, the gap size may bedetected by using X-ray fluoroscopy to observe the contrast portionwhich is disposed in a portion of the strut or the support portion andwhich is configured to include an X-ray contrast material. In thismanner, the position and the expansion diameter of the strut or thesupport portion can be accurately adjusted while the gap of the stenosedsite is compared with the position and the expansion diameter by usingX-ray fluoroscopy, thereby further facilitating manual skills.

In addition, the present disclosure also provides another treatmentmethod (therapy method) for cutting substances inside a body lumen. Thetreatment method is adopted by using a medical device including atubular drive shaft that is rotatable, a tubular outer sheath that canaccommodate the drive shaft, at least one strut that rotatablyinterlocks with a distal side of the drive shaft, that extends along arotation axis, and whose central portion is bent so as to be expandableradially outward, a linear motion shaft that is arranged inside thedrive shaft, and that expands the strut by moving relative to the driveshaft in an axial direction, and a liquid supply unit that suppliesliquid to any one of a portion between the outer sheath and the driveshaft and a portion between the drive shaft and the linear motion shaft.The treatment method can include (i) a step of inserting the strut in acontracted state into the body lumen, (ii) a step of expanding the strutby moving the linear motion shaft to the drive shaft, (iii) a step ofcutting the substances inside the body lumen by causing the drive shaftto rotate the strut, (iv) a step of causing the liquid supply unit tosupply the liquid to any one of the portion between the outer sheath andthe drive shaft and the portion between the drive shaft and the linearmotion shaft so that the liquid flows in a distal direction, in a statewhere the medical device is inserted into the body lumen, and (v) a stepof contracting the strut and removing the strut from the inside of thebody lumen. According to the treatment method configured as describedabove, the liquid flows in the distal direction through at least oneportion between the outer sheath and the drive shaft, and between thedrive shaft and the linear motion shaft. Accordingly, the blood becomesless likely to flow through at least one portion between the outersheath and the drive shaft, and between the drive shaft and the linearmotion shaft. Therefore, the blood is prevented from coagulating insidethe treatment device, and relative movements are properly maintainedbetween the respective tubular bodies. Accordingly, it is possible toprevent operability from becoming poor. In addition, since the blood canbe prevented from flowing outward via the medical device, safety can beimproved.

In addition, the present disclosure also provides further anothertreatment method (therapy method) for cutting substances inside a bodylumen. The treatment method is adopted by using a medical deviceincluding a drive shaft that is rotatable, at least one strut thatrotatably interlocks with a distal side of the drive shaft, that extendsalong a rotation axis, and whose central portion is bent so as to beexpandable radially outward, a support portion that is rotatably drivenby the drive shaft, that is formed in a mesh shape and a tubular shapewhile including multiple gaps, at least a portion of which is positionedon a radially inner side of the strut, and that is expandable radiallyoutward by a central portion in a direction extending along the rotationaxis being bent, and a detection unit that detects resistance includingat least any one of rotating direction resistance and axial directionresistance which act on the strut. The treatment method can include (i)a step of inserting the strut and the support portion which are in acontracted state into the body lumen, (ii) a step of expanding the strutand the support portion, (iii) a step of gradually cutting thesubstances while repeatedly pushing and pulling the substances insidethe body lumen by causing the drive shaft to rotate the strut and thesupport portion, (iv) a step of causing the detection unit to detect theresistance, (v) a step of stopping the rotation of the strut and thesupport portion when the resistance exceeds a preset threshold value orgiving a notification that the resistance exceeds the threshold value,and (vi) a step of contracting the strut and the support portion andremoving the strut and the support portion from the inside of the bodylumen. According to the treatment method configured as described above,when the resistance exceeds the preset threshold value, the rotation ofthe strut and the support portion is stopped, or the fact that theresistance exceeds the preset threshold value is notified. Accordingly,when excessive resistance acts on the strut, measures can be taken inorder to prevent the strut from being damaged or broken, therebyimproving safety.

In addition, the above-described treatment method may further include astep of contracting the strut and the support portion or moving thestrut and the support portion along the axial direction, after the stepof stopping the rotation of the strut and the support portion or givingthe notification that the resistance exceeds the threshold value. Inthis manner, when the strut restarts the cutting, the resistance actingon the strut is reduced. Accordingly, the strut can be prevented frombeing damaged or broken.

In addition, according to the above-described treatment method, in thestep of decreasing the diameter of the strut and the support portion ormoving the strut and the support portion along the axial direction, thestrut and the support portion may be moved in the proximal direction soas to be separated from the substances. In this manner, when the cuttingis restarted, the strut and the support portion can be pushed to thesubstances from the proximal side, thereby enabling the substances to becut effectively.

Without being limited to the above-described embodiments, the presentinvention can be modified in various ways by those skilled in the art,within the technical idea of the present invention. For example,according to the first embodiment, the blade 47 is formed on only thedistal side of the strut 41. However, the blade 47 may be formed on theproximal side of the strut 41, or may be formed on both the distal sideand the proximal side.

In addition, according to the first embodiment, one strut 41 has themultiple opening portions 45 formed therein. However, as illustrated inFIG. 31, one strut 160 may have only one opening portion 161 which iselongated in the extending direction of the strut 160, and the inneredge portion of the opening 161 may serve as a blade. The same referencenumerals are given to elements having the same function as that in theabove-described embodiments, and description thereof will be omitted.

In addition, according to the first embodiment, the inner edge portionof the opening 45 of the strut 41 serves as the blade 47. However, anoutside edge portion of the strut may serve as a blade.

In addition, without being limited to the blood vessel, the body lumeninto which the medical device 10 is inserted may include the vascular,the urinary tract, the biliary tract, the fallopian tube, the hepaticduct and the like.

In addition, at least any one of the cutting unit 40 and the supportportion 50 may be covered with a cover layer 170 configured to include ahydrophilic material, as in another modification example according tothe first embodiment, which is illustrated in FIG. 32. According to thisconfiguration, at least any one of the cutting unit 40 and the supportportion 50 is likely to slide between biological tissues. Accordingly,safety can be improved by preventing normal biological tissues frombeing damaged. The same reference numerals are given to elements havingthe same function as that in the above-described embodiments, anddescription thereof will be omitted.

For example, the hydrophilic materials include cellulose-based polymericsubstances, polyethylene oxide-based polymeric substances, maleicanhydride-based polymeric substances (for example, maleic anhydridecopolymer such as methyl vinyl ether-maleic anhydride copolymers),acrylamide-based polymeric substances (for example, polyacrylamide, andblock copolymer of polyglycidyl methacrylate-dimethylacrylamide(PGMA-DMAA)), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and the like.

In addition, the blade formed in the strut may be a polishing materialsuch as diamond particles or the like which are attached to the outersurface of the strut.

In addition, according to the first embodiment, the support portion 50is arranged on the radially inner side of the strut 41. However, aportion of the wire configuring the support portion may be arrangedoutside the strut. According to this configuration, a portion of thestrut which is not intended to come into contact with biological tissuesis covered with the wire. Therefore, it is possible to minimize damageto normal biological tissues.

In addition, according to the above-described first embodiment, thecutting unit 40 and the support portion 50 can be caused to expand so asto have any desired size by the operation in the operation unit 90.However, a configuration may be adopted in which the cutting unit 40 andthe support portion 50 cannot expand so as to have any desired size.Alternatively, a structure may be adopted in which the cutting unit andthe support portion expand by using self-restoring force.

In addition, according to the above-described first embodiment, thesupport portion 50 is formed by braiding the multiple wires 51. However,the support portion may be formed into a reticular shape by formingmultiple openings in a single member.

In addition, according to the above-described first embodiment, the feedscrew mechanism is employed in order to move the linear motion shaft 70.However, a structure is not limited thereto as long as the linear motionshaft 70 can be moved.

In addition, according to the above-described first embodiment, themotor 96 is employed in order to rotate the drive shaft 60. However,without being limited thereto, the drive source may be a gas turbine,which is rotated by using high pressure gas such as nitrogen gas or thelike, for example.

In addition, at least a portion of the cutting unit and the supportportion may be formed so that the material thereof includes the X-raycontrast material. In this manner, it is possible to accuratelyrecognize the position by using X-ray fluoroscopy, thereby furtherfacilitating manual skills. For example, the X-ray contrast materialspreferably include gold, platinum, platinum-iridium alloy, silver,stainless steel, molybdenum, tungsten, tantalum, palladium, alloythereof or the like.

In addition, according to a modification example of the secondembodiment, which is illustrated in FIG. 33, a distal end portion 411 ofa cutting unit 410 may be fixed to the distal end portion 234 of thesupport portion 230, and a proximal end portion 412 of the cutting unit410 may be fixed to the proximal end portion 235 of the support portion230 and the drive shaft 240. Accordingly, the proximal end portion 412of the cutting unit 410 is movable in the axial direction relative tothe proximal end portion 235 of the support portion 230 and the driveshaft 240. The proximal end portion 235 of the support portion 230 isfixed to the drive shaft 240, and the distal end portion 234 of thesupport portion 230 is fixed to the linear motion shaft 250. Even inthis configuration, the distal end portion 234 and the proximal endportion 235 of the support portion 230 are moved close to each other. Inthis manner, force acting in the axial direction does not act betweenthe distal end portion 411 and the proximal end portion 412 of thecutting unit 410. The strut 41 of the cutting unit 410 can be caused toexpand by only force acting radially outward which is received from thesupport portion 230. The same reference numerals are given to elementshaving the same function as that in the above-described embodiments, anddescription thereof will be omitted.

In addition, as in another modification example of the secondembodiment, which is illustrated in FIG. 34, an expandable andcontractible interlock portion 420 which interlocks the proximal portionof the linear motion shaft 250 and the proximal portion of the driveshaft 240 with each other may be formed into a bellows shape. If theinterlock portion 420 has the bellows shape, the interlock portion 420is likely to expand and contract in the axial direction. The samereference numerals are given to elements having the same function asthat in the above-described embodiments, and description thereof will beomitted.

In addition, as in further another modification example of the secondembodiment, which is illustrated in FIG. 35, the outer sheath 270 maynot interlock with a first housing 431 of a liquid supply unit 430, anda third sealing portion 432 may be disposed on the further distal sidefrom the port portion 357 disposed in the first housing 431. Then, in adrive shaft 440, a hole portion 441 is formed between the first sealingportion 355 and the third sealing portion 432. The outer surface of thedrive shaft 440 is covered with a second cover portion 442 fordecreasing a frictional force by coming into slidable contact with thethird sealing portion 432. According to this configuration, withoutsupplying the physiological salt solution from the container bag 352 toa portion between the outer sheath 270 and the drive shaft 440, thephysiological salt solution can be caused to flow into a portion betweenthe drive shaft 440 and the linear motion shaft 250 via the hole portion441. The physiological salt solution flowing into the drive shaft 440can flow into the linear motion shaft 250 after passing through the holeportion 251 of the linear motion shaft 250. The physiological saltsolution flowing into the linear motion shaft 250 can flow into thelumen 281 of the inner tube 280 after passing through the hole portion282 of the inner tube 280. The same reference numerals are given toelements having the same function as that in the above-describedembodiments, and description thereof will be omitted.

The detailed description above describes medical device and treatmentmethod. The invention is not limited, however, to the preciseembodiments and variations described. Various changes, modifications andequivalents can effected by one skilled in the art without departingfrom the spirit and scope of the invention as defined in theaccompanying claims. It is expressly intended that all such changes,modifications and equivalents which fall within the scope of the claimsare embraced by the claims.

What is claimed is:
 1. A medical device for cutting substances inside abody lumen, the medical device comprising: a drive shaft that has arotation axis extending in an axial direction and is rotatable aroundthe rotation axis, the drive shaft connected to a motor configured torotate the drive shaft around the rotation axis; a plurality of strutsthat extend along the rotation axis and are arranged around the rotationaxis with an interval, the plurality of struts having a distal end and aproximal end, each of the plurality of struts bridging between thedistal end and the proximal end; the distal end of the plurality ofstruts being attached to a distal side of the drive shaft, the pluralityof struts configured to rotate around the rotation axis incorrespondence with a rotation of the drive shaft; the plurality ofstruts being deformable in correspondence with two states, the twostates being a contraction state and an expansion state, in thecontraction state, the distal end and the proximal end of the pluralityof struts are most distant in the axial direction, in the expansionstate, the distal end and the proximal end of the plurality of strutsare brought closer in the axial direction such that central portions ofthe plurality of struts are bent and expanded in a radial direction ofthe rotation axis, the radial direction being perpendicular to the axialdirection, the central portions being determined by a half distance ofthe plurality of struts in the axial direction; in the contractionstate, seen from a side perspective of the medial device, at least oneof the plurality of struts, which is defined as one strut, has a centralportion in a generally linear shape extending along the axial direction,the central portion of the one strut being generally parallel to therotation axis of the drive shaft, wherein the central portion of the onestrut is determined by a half distance of the one strut in the axialdirection, and a titling portion, which is curved in shape, the tiltingportion being arranged on a proximal side of the central portion of theone strut and tilting with respect to the axial direction, the tiltingportion being convex in shape between a distal portion of the tiltingportion and a proximal portion of the tilting portion, and wherein theside perspective is determined as a view along the radial direction ofthe rotation axis, and wherein the one strut has a first width extendingfrom a distal end of the central portion of the one strut to a proximalend of the titling portion of the one strut; and in the expansion state,the central portion of the one strut is further away from the rotationaxis than the tilting portion of the one strut.
 2. The medical deviceaccording to claim 1, wherein the one strut includes a blade for cuttingthe substances formed at a position on a further distal side from aportion which expands most radially outwardly in the expansion state. 3.The medical device according to claim 1, wherein the one strut has asecond width whose width in a rotating direction is relatively widerthan that of an adjacent portion, the second width being distal of thecentral portion of the one strut; and when the one strut is brought intothe expansion state, an outer peripheral surface of a portion having ablade formed in the outer peripheral surface tilts radially inwardly asthe one strut goes toward a side in a rotating direction.
 4. The medicaldevice according to claim 1, further comprising: a distal tube disposedat a further distal side from the one strut, the distal tube having atubular shape, and whose outer peripheral surface has multiple convexportions formed on the distal tube and which is rotatable together withthe drive shaft.
 5. The medical device according to claim 1, wherein theone strut further has a leading portion that is determined from thedistal end to the central portion, and the leading portion of the onestrut is arranged parallel to the drive shaft in the contraction state,seen from the axial direction.
 6. The medical device according to claim1, wherein the tilting portion is not entirely present on an extensionline that is linearly extended from the central portion in the axialdirection.
 7. The medical device according to claim 1, wherein seen froma side view at which the central portion of the one strut and the driveshaft overlap, the tilting portion is not overlapped with the driveshaft.
 8. The medical device according to claim 1, wherein in theexpansion state, the tilting portion has an inflection point between thecentral portion of the one strut and the proximal portion of the tiltingportion seen from the side perspective.
 9. The medical device accordingto claim 1, wherein the curved shape of the tilting portion is from adistal end of the titling portion to a proximal end of the tiltingportion.
 10. The medical device according to claim 1, wherein the distalportion of the tilting portion and the proximal portion of the tiltingportion are arranged in a plane that intersects the rotation axis of thedrive shaft at more than one point, and in the contraction state, astart point of the tilting portion and an end point of the titlingportion are an extension of the central portion of the one strut.
 11. Amedical device that cuts subjects inside a body lumen, the medicaldevice comprising: a drive shaft that has a rotation axis extending inan axial direction and is rotatable around the rotation axis, the driveshaft connected to a motor configured to rotate the drive shaft aroundthe rotation axis; a plurality of struts that extend along the rotationaxis and are arranged around the rotation axis with an interval, theplurality of struts having a distal end and a proximal end, each of theplurality of struts bridging between the distal end and the proximalend, wherein the proximal end of the struts is attached to the driveshaft such that the plurality of struts are configured to rotate aroundthe rotation axis in correspondence with a rotation of the drive shaft,the plurality of struts being deformable in correspondence with twostates, the two states being a contraction state and an expansion state,in the contraction state, the distal end and the proximal end are themost distant in the axial direction, and in the expansion state, thedistal end and the proximal end are brought closer in the axialdirection such that central portions of the plurality of struts are bentand expanded in a radial direction of the rotation axis, which isperpendicular to the axial direction, the central portions beingdetermined by a half distance of the plurality of struts in the axialdirection; in the contraction state, seen from a side perspective of themedial device, at least one of the plurality of struts, which is definedas one strut, has a central portion in a generally linear shapeextending along the axial direction, the central portion of the onestrut being generally parallel to the rotation axis of the drive shaft,wherein the central portion of the one strut is determined by a halfdistance of the one strut in the axial direction, and has a tiltingportion, and wherein the tilting portion is in a curved shape and islinearly connected from and located in proximity to the proximal endthat is attached to the drive shaft, the tilting portion being convex inshape between a distal portion of the tilting portion and a proximalportion of the tilting portion, and wherein the side perspective isdetermined as a view along the radial direction of the rotation axis,and wherein the one strut has a first width extending from a distal endof the central portion of the one strut to a proximal end of the titlingportion of the one strut; in the expansion state, the central portion ofthe one strut is further away from the rotation axis than the tiltingportion of the one strut; the drive shaft is a tubular body; the medicaldevice further comprises a linearly moving shaft that is disposed insidethe drive shaft, wherein the linearly moving shaft is coaxial to thedrive shaft and relatively movable toward a distal side and a proximalside in the axial direction in relation to the drive shaft, and thelinearly moving shaft is rotatable together with the drive shaft; thelinearly moving shaft is a tubular body having a hollow inside such thata guide wire is to be inserted through the hollow inside of linearlymoving shaft; the linearly moving shaft penetrates the plurality ofstruts from the proximal end to the distal end of the struts; and aportion of the linearly moving shaft, which penetrates the distal end ofthe struts, is directly or indirectly connected to the distal end of thestruts such that, when the linearly moving shaft moves toward the distalside, the plurality of struts approach the contraction state, when thelinearly moving shaft moves toward the proximal side, the plurality ofstruts approach the expansion state.
 12. The medical device according toclaim 11, wherein when the one strut is brought into the expansionstate, an outer peripheral surface of a portion having a blade formed inthe outer peripheral surface tilts radially inwardly as the one strutgoes toward a side in a rotating direction.
 13. The medical deviceaccording to claim 1, wherein remaining struts among the plurality ofstruts, which are other than the one strut, are identical to the onestrut in their shape, each of which has a tilting portion positionedbetween the central portion and the proximal end, and the plurality ofstruts being evenly arranged around the rotation axis, seen from theaxial direction, and wherein the distal end and the proximal end of theeach of the plurality of struts are arranged around the rotation axis ina same location on a distal side and a proximal side of the plurality ofstruts.
 14. The medical device according to claim 13, furthercomprising: a support portion being rotatably connected to the distalside of the drive shaft, the support portion including maximum expansionportions configured to protrude radially outward and beyond theplurality of struts from a portion between the plurality of struts inthe expansion state.
 15. The medical device according to claim 11,wherein in the expansion state, the tilting portion has an inflectionpoint between the central portion of the one strut and the proximalportion of the tilting portion seen from the side perspective.
 16. Themedical device according to claim 11, wherein the curved shape of thetilting portion is from a distal end of the titling portion to aproximal end of the tilting portion.
 17. The medical device according toclaim 11, wherein the distal portion of the tilting portion and theproximal portion of the tilting portion are arranged in a plane thatintersects the rotation axis of the drive shaft at more than one point,and in the contraction state, a start point of the tilting portion andan end point of the titling portion are an extension of the centralportion of the one strut.
 18. A medical device for cutting substancesinside a body lumen, the medical device comprising: a drive shaft thathas a rotation axis extending in an axial direction and is rotatablearound the rotation axis, the drive shaft connected to a motorconfigured to rotate the drive shaft around the rotation axis; aplurality of struts that extend along the rotation axis and are arrangedaround the rotation axis with an interval, the plurality of strutshaving a distal end and a proximal end, each of the plurality of strutsbridging between the distal end and the proximal end; the distal end ofthe plurality of struts being attached to a distal side of the driveshaft, the plurality of struts configured to rotate around the rotationaxis in correspondence with a rotation of the drive shaft; the pluralityof struts being deformable in correspondence with two states, the twostates being a contraction state and an expansion state, in thecontraction state, the distal end and the proximal end of the pluralityof struts are most distant in the axial direction, in the expansionstate, the distal end and the proximal end of the plurality of strutsare brought closer in the axial direction such that central portions ofthe plurality of struts are bent and expanded in a radial direction ofthe rotation axis, the radial direction being perpendicular to the axialdirection, the central portions being determined by a half distance ofthe plurality of struts in the axial direction; in the contractionstate, seen from a side perspective of the medial device, at least oneof the plurality of struts, which is defined as one strut, has a centralportion in a generally linear shape extending along the axial direction,the central portion of the one strut being generally parallel to therotation axis of the drive shaft, wherein the central portion of the onestrut is determined by a half distance of the one strut in the axialdirection, and a titling portion, which is curved in shape, the tiltingportion tilting with respect to the axial direction, the tilting portionbeing convex in shape between a distal portion of the tilting portionand a proximal portion of the tilting portion, and wherein the sideperspective is determined as a view along the radial direction of therotation axis, and wherein the one strut has a first width extendingfrom a distal end of the central portion of the one strut to a proximalend of the titling portion of the one strut; and in the expansion state,the central portion of the one strut is further away from the rotationaxis than the tilting portion of the one strut.
 19. The medical deviceaccording to claim 18, wherein the one strut includes a blade forcutting the substances formed at a position on a further distal sidefrom a portion which expands most radially outwardly in the expansionstate.
 20. The medical device according to claim 18, wherein theplurality of struts are evenly arranged around the rotation axis, seenfrom the axial direction, and wherein the distal end and the proximalend of the each of the plurality of struts are arranged around therotation axis in a same location on a distal side and a proximal side ofthe plurality of struts; and a support portion being rotatably connectedto the distal side of the drive shaft, the support portion includingmaximum expansion portions configured to protrude radially outward andbeyond the plurality of struts from a portion between the plurality ofstruts in the expansion state.